System and method for re-directing requests from browsers for communication over non-IP based networks

ABSTRACT

A method and system for deploying content to client applications is provided. Inbound messages are accepted from a client application running on a client device via a proxy IP/port. The inbound messages are packaged into an internal message format with an HTTP redirector. The packaged message is forwarded to a back-end server via a message router. A response is received form from a web server. The response is packaged into the internal message format with the back-end server. The response is then forwarded to the HTTP redirector via a message router. The response can then be transferred to the client application running on the client device, via the proxy IP/port.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

The present application is a continuation application of U.S. patentapplication Ser. No. 12/659,737 entitled “System and Method forRe-Directing Requests from Browsers for Communications over Non-IP basedNetworks” to Zombek et al., filed on Mar. 19, 2010, now U.S. Pat. No.8,200,829, which is a continuation application of U.S. patentapplication Ser. No. 11/327,413 entitled “System and Method forRe-Directing Requests from Browsers for Communications over Non-IP basedNetworks” to Zombek et al., filed on Jan. 9, 2006, now U.S. Pat. No.7,689,696, which is a continuation-in-part application of U.S. patentapplication Ser. No. 09/494,553, entitled “A Messaging Method andApparatus for Sending and Receiving Messages In a Client ServerEnvironment Over Multiple Wireless Networks,” to Zombek, et al., filedon Jan. 31, 2000, which is a continuation-in-part application of U.S.patent application Ser. No. 09/694,297, entitled “A Messaging Method andApparatus for Sending and Receiving Messages in a Client SeverEnvironment Over Multiple Wireless Networks,” to Zombek, et al., filedon Oct. 24, 2000, and a continuation-in-part application of U.S. patentapplication Ser. No. 09/698,181, entitled “A System and Method forRe-Directing Requests from Browsers for Communication Over Non-IP BasedNetworks,” to Zombek, et al., filed on Oct. 30, 2000, now U.S. Pat. No.7,003,571, of common assignee to the present invention, the contents ofall of which are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates in general to the field of communicationsand more particularly to messaging between client devices and serversover multiple wireless networks that use different access protocols.

BACKGROUND OF THE INVENTION

Recent advances in hardware and communication technologies have broughtabout an era of client computing over wired and wireless networks. Theproliferation of powerful notebook computers and wireless client devicespromises to provide client end users with network access at any time andin any location over various networks, including the Internet. Thiscontinuous connectivity allows users to be quickly notified of changingevents, and provides them with the resources necessary to respond inrealtime even when in transit. For example, in the financial servicesindustry, online traders and financial professionals may be given thepower to access information in real-time, using wireless client devices.

Conventionally, however, developers of complex, wireless messagingsolutions have been forced to develop applications that are specific tovarious device types and network access protocols in diverse enterprisearchitectures and platforms. In other words, conventional clientcomputing solutions have been largely platform-specific,network-specific, or both. For example, messages may be generated by awide variety of applications running on a wide variety of clientdevices, such as Palm computing platform devices, Windows CE devices,paging and messaging devices, laptop computers, data-capable smartphones, etc. Depending on the type of network used by service providers,the client-generated messages may be transported over networks havingvarious access protocols, such as, e.g., Cellular Digital Packet Data(CDPD), Mobitex, dial-up Internet connections, Code Division MultipleAccess (CDMA), Global System for Mobile Communications (GSM), andReFlex. As a result, current developers of client computing solutionsmust have intimate knowledge of specific network characteristicsincluding, e.g., wireless network characteristics, protocolenvironments, and wireless links channel characteristics. Therefore,there exists a need to simplify wireless client and server applicationdevelopment environments to support the wide variety of device andnetwork dependent architectures.

Messaging Application Programming Interface (MAPI) is a messagingarchitecture and an interface component for applications such aselectronic mail, scheduling, calendaring and document management. As amessaging architecture, MAPI provides a consistent interface formultiple application programs to interact with multiple messagingsystems across a variety of hardware platforms. MAPI provides crossplatform support through such industry standards as Simple Mail TransferProtocol (SMTP), X.400 and common messaging calls. MAPI is also themessaging component of Windows Open Services Architecture (WOSA).

Accordingly, MAPI is built into such operating systems as, e.g., Windows95, Windows 98, Windows NT and Windows 2000, available from MicrosoftCorporation of Redmond, Wash., U.S.A. and can be used by 16-bit and32-bit Windows applications. For example, a word processor can senddocuments and a workgroup application can share and store differenttypes of data using MAPI. MAPI separates the programming interfaces usedby the client applications and the service providers. Every componentworks with a common, Microsoft Windows-based user interface. Forexample, a single messaging client application can be used to receivemessages from fax, a bulletin board system, a host-based messagingsystem and a LAN-based system. Messages from all of these systems can bedelivered to a single “universal inbox.”

Transmission Control Protocol (TCP) is a transport layer protocol usedby an application in one host to communicate with an application inanother host. This is accomplished by services provided by the protocollayers beneath the transport layer in both hosts. As aconnection-oriented protocol TCP requires the establishment of aconnection between the two hosts before two applications are able tocommunicate. TCP manages the connection and once both applications havecommunicated all required information between themselves the connectionis released as if the connection is two simplex connections as opposedto a single duplex connection. The information is transferred betweenapplications on different hosts is a byte stream. The transport layerhides message transfer details such as segmentation, ordering andduplication from the applications and provides end-to-endacknowledgement.

The Internet Protocol (IP) layer provides certain services to thetransport layer protocol including hiding the details of the physicaland data link layers and the services provided by them from thetransport layer protocol. The IP layer provides a datagram deliveryservice. A datagram is a unit of data less than an entire message. Amessage may be, for example, a file, which may be quite large. Sincethere is a maximum size for a message (or file), the message may have tobe segmented and transferred in smaller units. These smaller units arethus called datagrams. Each datagram is sent over the network as aseparate entity and may, in fact, follow separate paths to thedestination host. At the destination host, the datagrams are reassembledin proper order (usually in a buffer area) by the transport layer. Eachnode on the network sends any datagrams on to a next node onlyconsidering the final destination and only acknowledges receipt of thedatagram to the preceding node. That is, the IP layer does not provideend-to-end acknowledgement. End-to-end acknowledgement is a service ofthe transport layer protocol. Should any node-to-node acknowledgementsnot be received by the preceding node, the datagram or datagramsunacknowledged will be retransmitted. The transport layer in thedestination host will also acknowledge any duplicated datagrams (elsereceipt of duplicate datagrams will continue resulting in a cloggednetwork) and ignore them.

Routing between network nodes is accomplished by means of muting tables.These routing tables can be static or dynamic and result in datagramsbeing forwarded from a source host to a destination host one node at atime. The intermediate nodes are often called “hops.”

The acronym, TCP/IP, is also used to refer to a five layer protocolmodel similar to the ISO/OSI seven layer protocol model. The TCP/IPmodel does not have the equivalent to layers 5 and 6 of the ISO/OSIprotocol model. A protocol model defines the protocol layers and theinterfaces between the layers. When implemented in software, hardware orfirmware or possibly field programmable gate arrays (FPGAs), theimplementation provides the actual services. This layered approachallows for ease of upgrading so long as the interface to the layerimmediately above or below is not altered. Layering also allows forcomplete substitution. For example, should a new physical medium becomeavailable then so long as the interface between layer two and layer oneremain the same, an old physical layer implementation module can beremoved and a new implementation module substituted. In the alternative,the new implementation module could be added as another option. That is,the protocol suite defines the rules and the implementation provides theservices that allow the communications to take place betweenapplications on different hosts. The implementation of the TCP layerprovides for the application to require a certain Quality of Service(QOS) as specified by a set of parameters including but not limited topriority, transmission delay, throughput etc.

Another well-known transport layer protocol is known as User DatagramProtocol (UDP), which is a connectionless transport protocol. The basicdata transfer unit is the datagram. A datagram is divided into headerand data areas as it is for the IP layer. An additional header over andabove the IP header is used. The UDP header contains source anddestination addresses (ports), a UDP length field (the length includesthe 8 byte header and the data) and a UDP checksum. The UDP dataincludes the IP header and data. The IP layer supports UDP as aconnectionless transport protocol for use in transmitting, for example,one time request-reply type messages or applications where time is ofgreater importance than accuracy.

TCP is used by applications on different hosts to communicate over anassumed unreliable network. To accomplish such communication much isadded to the protocol in order to ensure that the informationtransferred over the network is valid. This addition has a cost and thatcost is increased overhead with the attendant increase in bandwidth. AUDP header is eight bytes, the TCP header is 24 bytes and an IP headeris a minimum of 20 bytes. Therefore, UDP/IP headers are a minimum of 28bytes and TCP/IP headers are a minimum of 44 bytes. This is fairly largein terms of overhead and bandwidth utilization particularly overwireless networks. There are other significant problems with usingstandard TCP/IP over wireless networks principally in the area of flowcontrol. The UDP/IP protocol combination, while not offering anyguarantees to users, is expected to be reliable. Wireless networks tend,however, by their nature to be lossy. Several. solutions have beenproposed when the network is not homogeneous. That is, when the networkhas both wireless and wireline portions. One suggestion is to useindirect TCP and another is to use snooping.

Other protocols such as Serial Line IP (SLIP) and Point to PointProtocol (PPP) have been developed. SLIP is not a standard and both arefor point to point connections only so are not available for uses innetworks. CDPD vendors indicate that they provide an integrated TCP/IPstack but it is not known the cost in terms of bandwidth overhead.

Conventionally, the existing wireless protocols do not provide anend-to-end solution over multiple networks and multiple client devices.Therefore, in addition to the need for a common architecture through asingle, user friendly methodology for providing effective and reliablewireless data solutions for hand-held and laptop computing devices,wireless networks, and legacy systems, there also exists a need toefficiently and reliably communicate data using minimum bandwidth.

SUMMARY OF THE INVENTION

The present invention features a system, method and computer programproduct that in an exemplary embodiment is operative to provide amulti-network transport programming interface that can enableclient/server applications to be written easily, where such applicationscan allow client applications running on client devices to communicatemessages with server applications across one or more wireless andwire-line networks. Moreover, the present invention in an exemplaryembodiment offers features for communicating such messages over wirelessnetworks efficiently, without requiring significant bandwidth, avaluable resource in wireless networks.

Briefly, the present invention in an exemplary embodiment includes asystem for communicating messages in a client-server environment overone or more wireless networks that can support different networkprotocols. In an exemplary embodiment, the system of the inventionincludes a client device operative to execute a client application, anda back-end server (BES) operative to execute a server application. In anexemplary embodiment, a protocol gateway (PG) can encapsulate anunderlying network protocol of the plurality of wireless networks. In anexemplary embodiment, a client application and the server applicationcan communicate messages with each other through the PG independently ofthe underlying network protocol of the wireless network used for suchcommunication.

Conventional session-based transport protocols (e.g. TCP) are designedfor LAN-based systems with little network latency. These session-basedtransport protocol implementations are extremely chatty and were notdesigned to consider the amount of bytes sent over the network tomaintain the state of a connection.

Advantageously, the present invention, in an exemplary embodiment,features a highly optimized semi-reliable data transport protocol,simple network transport layer (SNTL). The transport protocolimplementation, in an exemplary embodiment, can optimize the over theair communication by using a connectionless send and receive mechanism.In addition, or alternatively, in an exemplary embodiment, the presentinvention can provide multiple compression mechanisms to reduce theamount of information that needs to be sent over the air. In anexemplary embodiment, in order to provide a reliable mechanism over aconnectionless environment, the transport protocol implementation canprovide for message segmentation and reassembly, message retries, ormessage ACK and NACK service for each supported wireless network. In anexemplary embodiment, message segments that are not acknowledged by thepeer protocol layer within the configurable time frame can be retriedautomatically by the transport protocol implementation. In order tofacilitate the request and provision of services, the interfaces betweenlayers can be clearly defined for peer-to-peer communication betweencorresponding layers of both sides of a connection. That is, theprotocol stack on each side (client and server) can be symmetrical. Thiscan allow two machines to specify how they communicate with one anotheron a level-to-level basis, rather than having to negotiate one giantprotocol for the entire network. This means that logical communicationscan occur at the peer protocol layer. On the client side for wirelesscommunications this can be called a peer wireless protocol layer. In anexemplary embodiment, the client or server applications do not need tobe concerned with segmenting the message and performing message reties.In addition to performing message retries, the transport protocolimplementation can support message duplication detection. In anexemplary embodiment, to support this reliable mechanism over aconnectionless environment, the transport protocol implementation canadd only four to six bytes to each application message. In an exemplaryembodiment, SNTL can include a novel and non-obvious hybrid protocolincluding many of the advantages of TCP but connectionless as is UDP.Further, in an exemplary embodiment, there can be less overhead than isrequired by conventional TCP.

The present invention, in an exemplary embodiment, can also use awireless connectivity middle layer gateway, which can be developed usinga wireless software development environment. The environment caninsulate a developer from the complexities of the underlying detailsrelated to devices and protocols.

In an exemplary embodiment, the environment can be packaged,advantageously, as a software development toolkit (SDK). The developercan work at the application layer by using the SDK. The SDK, in anexemplary embodiment, can include, e.g., software libraries for clientand/or server application development. The present invention, in anexemplary embodiment, can support solutions and software engineeringusing technologies such as, e.g., Windows NT/95/98/2000, Open DatabaseConnection (ODBC) compliant databases, Palm OS, and Windows CE clientdevices, and CDPD, Mobitex and dial-up networks.

Advantageously, wireless technologies and client devices can remaintransparent to the data source through the use of client and serverapplication programming interfaces (APIs) that can support multipleoperating environments including, for example, Palm OS, RIM, Windows 95,98, 2000, CE and NT, UNIX, Linux, and other variations of UNIX, etc.These well-defined APIs can use a set of portable class libraries to aidin rapid application development. Access to the intelligent messagingnetwork of the present invention can be via wireless client devices orvia a dial-up or leased line or other wireline connection coupled via,e.g., an Internet service provider (ISP), a network service provider(NSP), a private network, or a virtual private network (VPN). That is,enterprise support, can be provided for and to, wireless clients andclients that need to access the intelligent messaging network of thepresent invention via a wired connection or dial-up line. This lattergroup of clients can be called Internet proxy clients, i.e., clientsthat can use a proxy server for access to the Internet. As clientdevices and wireless network technologies evolve, this system can ensurethat data solutions are supported.

In an exemplary embodiment, a method and system for deploying content toclient applications is provided. Inbound messages are accepted from aclient application running on a client device via a proxy IP/port. Theinbound messages are packaged into an internal message format with anHTTP redirector. The packaged message is forwarded to a back-end servervia a message router. A response is received form from a web server. Theresponse is packaged into the internal message format with the back-endserver. The response is then forwarded to the HTTP redirector via amessage router. The response can then be transferred to the clientapplication running on the client device, via the proxy IP/port.

In another embodiment, a wireless device for communicating with a servervia a wireless network is provided. The wireless device can include abrowser generating a request. A redirector can receive the request via aproxy IP/port. The redirector may then package the request with aprotocol used by the wireless network.

The request may be fulfilled by the wireless network and transmitted tothe wireless device. In one embodiment, the request may be an HTTPrequest. The HTTP request can be sent from a proxy server to anappropriate web server. A response is received to the request. Theresponse may then be packaged into a message format used by the wirelessnetwork. The packaged response is sent to a redirector. The packagedresponse can be unpacked with the redirector and provided the to a webbrowser.

In another exemplary embodiment, a method of deploying content from oneof a plurality of servers, through a message router and over a wirelessnetwork to a client application, which is running on one or more of aplurality of client devices, is provided. An inbound message can becreated with a redirector at the client device. The inbound message mayinclude a message key. The inbound message can be sent from the clientdevice and accepted at the message router. The inbound message may beforwarded to a selected one of the plurality of servers based on themessage key.

A further embodiment includes a messaging system. The messaging systemmay comprise. A client device having a web browser and a redirectorcommunicating with the web browse. The redirector can package messagesfrom the web browser in a fundamental network protocol. A plurality ofwireless networks, each of which is adapted to communicate messagesbetween the client device and a server and support one or more wirelessnetwork protocols, may be provided. A protocol gateway can encapsulatethe fundamental network protocol, which underlies each of the one ormore wireless network protocols. Also, means for communicating messagesbetween the web browser and the server, over a selected wireless networkprotocol through the protocol gateway, independent of the selectedwireless network protocol should be included.

A computer useable information storage medium storing computer readableprogram code may be provided to carry out the method. For example, anembodiment of the invention may include a computer useable informationstorage medium storing computer readable program code for causing acomputer to perform the steps of:

accepting inbound messages from a client application running on a clientdevice;

packaging the inbound messages into an internal message format with aredirector;

forwarding the packaged message to a back-end server,

receiving a response from a web server;

packaging the response into the internal message format with theback-end server,

forwarding the response to the redirector, and

transferring the response to the client application running on theclient device.

Further features and advantages of the invention, as well as thestructure and operation of various exemplary embodiments of theinvention, are described in detail below with reference to theaccompanying drawings. In the drawings, like reference numbers generallyindicate identical, functionally similar, and/or structurally similarelements. The drawing in which an element first appears is indicated bythe leftmost digits in the corresponding reference number.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention will beapparent from the following, more particular description of an exemplaryembodiment of the invention, as illustrated in the accompanyingdrawings.

FIG. 1A is a block diagram of an exemplary embodiment of a communicationsystem that advantageously incorporates a messaging system according tothe present invention;

FIG. 1B is a high level block diagram of an exemplary embodiment of thepresent invention including an exemplary protocol gateway coupled to anexemplary message router which is coupled to an exemplary back-endserver;

FIG. 1C is an exemplary embodiment illustrating messaging routingaccording to the present invention;

FIG. 1D is an exemplary embodiment illustrating a protocol gateway (PG)startup sequence according to the present invention;

FIG. 1E is an exemplary embodiment illustrating a message router (MR)startup sequence according to the present invention;

FIG. 1F is an exemplary embodiment illustrating a back end server (BES)startup sequence according to the present invention;

FIG. 2 is a block diagram of an exemplary embodiment of a redirectorthat interacts with a browser and the intelligent messaging network thatis part of the system of FIG. 1A;

FIG. 3 depicts an exemplary embodiment of the proprietary protocol stackof the present invention;

FIG. 4 is an exemplary embodiment of a flow diagram numericallydepicting a flow of messages that corresponds to an authenticationchallenge success;

FIG. 5 is an exemplary embodiment of a flow diagram numericallydepicting a flow of messages that corresponds to an authenticationchallenge failure;

FIG. 6A is an exemplary embodiment of a flow diagram numericallydepicting a flow of messages that corresponds to a client applicationrequest to Back-End Server;

FIG. 6B is an exemplary embodiment of a flow diagram numericallydepicting a flow of multi-segment messages that corresponds to a clientapplication request to a Back-End Server;

FIG. 7A is an exemplary embodiment of a flow diagram numericallydepicting a flow of messages that corresponds to a Back-End Serverresponse to client application;

FIG. 7B is an exemplary embodiment of a flow diagram numericallydepicting a flow of multi-segment messages that corresponds to aBack-End Server (BES) response to client application, or alternativelyan alert generated by the BES;

FIG. 8A is an exemplary embodiment of a flow diagram numericallydepicting a flow of messages that corresponds to a Back-End Server alertto client application;

FIG. 8B is an exemplary embodiment of a flow diagram depicting a flow ofmessages providing an exemplary hybrid alert to an alternate clientdevice according to the present invention;

FIG. 8C is an exemplary embodiment of a flow diagram depicting a flow ofmessages representing an exemplary request and alert that could giverise to sending of a hybrid alert according to FIG. 8B according to thepresent invention; and

FIG. 9 is an exemplary embodiment of a diagram illustrating an exemplarymessage header according to the present invention.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT OF THE INVENTION

A preferred embodiment of the invention is discussed in detail below.While specific implementations are discussed, it should be understoodthat this is done for illustration purposes only. A person skilled inthe relevant art will recognize that other components and configurationsmay be used without parting from the spirit and scope of the invention.

FIG. 1A depicts a block diagram of a communication system 100 thatadvantageously can incorporate the present invention including one ormore client devices 112 a-c, collectively referred to as client devices112. The client devices 112 can execute corresponding clientapplications, which can be developed to provide specific subscribersolutions. For example, service subscribers such as, e.g., client user102, as shown, can carry, e.g., Palm Pilot client devices, Windows CEbased client devices or other one-way or two-way messaging clientdevices 112 to, e.g., remain apprised of stock market activities andinitiate transactions while roaming within the coverage area of theirrespective wireless service providers.

As described in detail below, the communication system 100 can supportan intelligent messaging network architecture (hereafter referred to as“intelligent messaging network”) according to the present invention. Theintelligent messaging network advantageously can incorporate amiddleware service in accordance with the present invention that canallow for the development of client and server applications independentof the underlying network protocols and device configurations. The basicmiddleware services offered by the intelligent messaging networkarchitecture can include, e.g., client-server connectivity, platformtransparency, network transparency, application tool support (throughthe use of APIs), network management, interaction with other networkservices, scalability and high availability.

System Overview

FIG. 1A depicts an exemplary embodiment of the communication system 100including a detailed block diagram of the present invention. Thecommunication system 100, in an exemplary embodiment, can be configuredto support a wide variety of wired and wireless access network protocolsvia an access network 114. The access network 114 protocols can include,e.g., dial-up modem, analog cellular, digital cellular, cellular digitalpacket data (CDPD), Mobitex, RIM, Ardis, iDEN, personal communicationsystem (PCS)-code division multiple access (CDMA) or time divisionmultiple access (TDMA), global system for wireless messaging (GSM),two-way and one-way paging (e.g., Reflex, Flex, etc.), as well asgeosynchronous earth orbit (GEO) or low earth orbit (LEO) satellitenetwork access protocols. The intelligent wireless messaging network ofthe present invention can provide network transparency to developers ofclient and server applications. As such, developers do not need toconcern themselves with implementation details of the underlying networkprotocols or with various platform specific encoding, such as, e.g.,big-endian and little-endian.

A number of the protocol gateways (PGs) 116 a, 116 b and 116 c,collectively PGs 116, can be configured to support a specific networkaccess protocol. The PGs 116, in an exemplary embodiment, can act as aninterface between a network 114 and wide-area/local-area networks(WANs/LANs) 118 a, and 118 b. The PGs 116 can provide the flexibility tosupport multiple present and future wireless access protocols such as,e.g., GPRS. Networks 118 collectively including networks 118 a and 118b, as shown, can be coupled to network 114 by, e.g., a router 114, andcan be protected from unauthorized access through a firewall 120.Networks 118 can include, e.g., a wide area network (WAN), local areanetwork (LAN), and/or the global Internet. Among other things, networks118 can include, e.g., one or more back-end servers (BESs) 122 a, 1221),and 122 c, collectively BESs 122, that can run server applications thatcan communicate messages with client applications running on the clientdevices 112. Via one or more message routers (MRs) 124 a, 124 b, and 124c, collectively MRs 124, these messages can be routed between the BESs122 and the PGs 116, and other network components. From the BESs 122,messages can be transmitted or delivered to, e.g., a content provider140. A specific type of BES shown as an HTTP Proxy BES 132 can be usedto send messages to an Internet server 142 such as a web server. Itshould be noted that although the present invention is described withreference to a specific exemplary architecture, a wide variety of WANsand LANs that can support wired and wireless environments are possible.

The PGs 116 can be responsible for sending and receiving applicationmessages between client applications and a BES 122 that can support theservice type of the application message. The message can be routed tothe BES 122 via the MR 124 as will described further below withreference to FIG. 1C. For each network access protocol that theintelligent messaging network supports, a corresponding PG 116 cansupport that network access protocol. PGs 116 can communicate directlywith one or more MRs 124 using, e.g., conventional TCP/IP communicationsor a modification of TCP/IP to address flow control between wireless andwireline networks. In an exemplary embodiment of the invention, the PGs116 can use clustering for, e.g., redundancy, scalability andload-balancing of incoming IP traffic across all the nodes within aconfigured cluster. In an exemplary embodiment, PGs 116 can provide loadbalancing by providing traffic to MRs 124 in, e.g., a round-robinfashion, which can, e.g., transmit to least recently used MR 124. Underthis arrangement, client applications can be configured to communicateto a single virtual IP address of the PG 116 cluster. Advantageously,this can provide the intelligent messaging network the flexibility todynamically start and stop the PGs 116 without disrupting service.Typically, the PGs 116 can run outside of the firewall 120. However, theintelligent messaging network architecture of the present invention doesnot preclude the PGs 116 from running inside an enterprise firewall 120.It will be apparent to those skilled in the art that alternativeconfigurations can also be used within the spirit and scope of thepresent invention.

The BESs 122 and MRs 124 can each have access to corresponding BES andMR databases (DBs) 126 and 128, respectively, which can store serverapplication and message routing parameters. Alternatively, a shareddatabase can be used to store information on an auxiliary memory devicesuch as, e.g., a storage area network (SAN). The BES DB 126 and MR DB128 can each maintain a common pool of information amongst the entiregroup of network servers. In an exemplary embodiment, this information,which can be independent of any specific messaging application, can bestored and accessed from a structured query language (SQL) database.

In order to assist network administrators in managing the intelligentmessaging network, the intelligent messaging network architecture canincorporate one or more simple network management protocol (SNMP)management consoles 130 a, 130 b, and 130 c, collectively SNMP console130, as the mechanism for network management. SNMP is a standard networkmanagement protocol widely used in conventional TCP/IP networks. Theconsole 130, e.g., can receive SNMP alerts. In an exemplary embodiment,a customer's SNMP console 130 can be “hooked” into, including such dataas might reside in, e.g., a management information base (MIB) 134 a. TheSNMP console 130 can be used to easily and effectively manage theintelligent messaging network of the present invention. In addition toproviding SNMP support, the intelligent messaging network can providenetwork administrators a tool to monitor the health of the network. AnSNMP console 130 can be placed in a network operations center (NOC) toadvantageously centrally manage the intelligent messaging network of thepresent invention.

An HTTP Redirector 106 can enable off-the-shelf web browsers such as,e.g., browser 104, to send and receive requests, such as, e.g.,hypertext transfer protocol (HTTP) requests, over the intelligentmessaging network. As described later, the HTTP Redirector 106 can workby intercepting HTTP requests from the browser 104 and can redirect themover the intelligent messaging network for fulfillment by an intelligentmessaging network HTTP proxy back end server 132 a, 132 b, or 132;collectively HTTP proxy back end servers (HBES) 132, which in turn canforward messages on to, e.g., other Internet servers 142. While theintelligent messaging network can provide a set of advanced services,the network can also offer support for external legacy services thatmight already be in use by an organization. By supporting other vendorservices such as, e.g. security, and databases, the intelligentmessaging network can fit into an existing legacy networkingenvironment, thereby allowing organizations to use their existingnetworking environment.

An Exemplary Implementation Embodiment of the Present Invention

In an exemplary implementation embodiment of the present invention, theIntelligent Messaging Network of the present invention can use an AetherIntelligent Messaging (AIM) Network (also referred to as AIM.net)developed by Aether Systems Inc., of Owings Mills, Md., U.S.A., theassignee of the present invention.

In an exemplary implementation embodiment, the BES 122 can be an AetherBack End Server (ABES) available from Aether Systems Inc., of OwingsMills, Md., U.S.A.

In an exemplary implementation embodiment, the PG 116 can be an AetherProtocol Gateway (APG), also previously referred to as a frontend server(FES), available from Aether Systems Inc., of Owings Mills, Md., U.S.A.

In an exemplary implementation embodiment, the MR 124 can be an AetherMessage Router (AMR) available from Aether Systems Inc., of OwingsMills, Md., U.S.A.

An exemplary embodiment of the MR DB 128 is an AIM database availablefrom Aether Systems, Inc. of Owings Mills, Md., U.S.

In an exemplary implementation embodiment, the SNMP Console 130 can bean Aether SNMP Network Management Console available from Aether SystemsInc., of Owings Mills, Md., U.S.A., which can include an SNMP compliantnetwork management application and hardware system platform.

In an exemplary implementation embodiment, the HTTP Proxy Back EndServer 132 cur be an Aether HTTP Proxy Back End Server available fromAether Systems Inc., of Owings Mills, Md., U.S.A.

It will be apparent to those skilled in the relevant art thatalternative implementations incorporating alternative or additionalcomponents, systems, operating systems, and applications could also beused within the spirit and scope of the present invention.

Software Development Environment

The intelligent messaging network, in an exemplary embodiment, canprovide multiple software development kits (SDKs) to assist, e.g.,engineers in developing client and server applications. The SDKs cancontain a consistent set of APIs and a set of platform specificlibraries for all intelligent messaging network supported platforms andnetworks. In addition to the SDKs, the intelligent messaging network canprovide developers a resource kit including a set of tools to assist thedevelopers when designing, implementing, and testing their client andserver applications.

As described later in detail, the intelligent messaging network canprovide, in an exemplary embodiment, a mobile client and server SDKenvironment to assist engineers developing client applications and BESs122. The SDKs can provide an easy to use API and a set of platformspecific libraries to perform, e.g., compression, network managementservices, server-to-server communication, serverregistration/de-registration, and reliable message transport services.

I. Common Network Services

In an exemplary embodiment, all of the servers, PGs 116, MRs 124, BESs122 can use, e.g., Windows NT 4.0 as their operating system availablefrom Microsoft Corporation of Redmond, Wash., U.S.A. Althoughalternative operating systems can be used in alternate embodiments, aswill be apparent to those skilled in the art, functionality of thepresent invention will be described in an exemplary Windows NT v.4.0environment. All the servers provide a set of common services,including, e.g.:

network management;

NT event logging;

message trace logging;

run as NT services;

server registration;

server de-registration; and

server-to-server TCP/IP communication.

The intelligent messaging network server SDK can encapsulate theimplementation of these core functions via application programminginterfaces (APIs) to insulate application developers from the hardware,software and protocol details of the underlying platforms. Providedbelow is a description of exemplary common services.

A. Network Management Service

All intelligent messaging network servers can support the standard SNMPGET, SET, and GET NEXT operations. In addition, the intelligentmessaging network servers can generate SNMP traps for notifying anetwork administrator of a critical event. The intelligent messagingnetwork Server SDK can provide a common MIB, for basic control andstatus-handling that is shared by all the intelligent messaging networkservers. In addition, the intelligent messaging network server SDK canprovide a MIB for each supported server type (i.e. PG 116, MR 124, HTTPProxy Back End Server 132, and BES 122). Developers developing BESs 122can define custom MIBs to support functions specific to theirapplication needs and can register the custom MIBs in a registered MIBsdatabase 134. Registration of a custom MIB with the SNMP console 130 canbe encapsulated by a set of network management APIs provided by theintelligent messaging network server SDK.

B. NT Event Logging Service

All intelligent messaging network servers can log critical information(e.g., start/stop time, and critical errors) to the NT event log on acorresponding platform on which they are running. Developers developingBESs 122 can log application specific events to the NT event log viaAPIs provided by the intelligent messaging network server SDK.

C. Message Trace Logging Service

All intelligent messaging network servers can optionally log inbound,outbound, and system events on the platform on which they are running.Developers developing BESs 122 can log application specific informationto an application-info-log via APIs provided by the intelligentmessaging network server SDK. In this way, developers are not requiredto know the implementation details of how to log a message to theinbound, outbound, or system-info-logs.

D. Run as NT Service

In an exemplary embodiment of the invention, all intelligent messagingnetwork servers can run as NT services. Rather than having each serverimplement the necessary code to run as an NT service, a utility programcalled AimServiceAny can be that can wrap NT service functionalityaround each intelligent messaging network server executable. Thebenefits of running a server as an NT service can include the followingadvantages:

-   -   Automatic Start on Reboot—Conventionally, when a reboot of a        machine is necessary, the user re-booting can also log on and        manually start any servers that need to be running on the        machine. With an AutoStart function provided by the        AimServiceAny, each intelligent messaging network server running        as an NT service can automatically restart before the user logs        on. This feature can be useful if, for example, the platform        reboots at night without human intervention.    -   No NT Logon Required to Run—As an added security measure,        intelligent messaging network servers can run without having        anyone logged onto the machine and, thus, can prevent        unauthorized users from accessing the platform and the servers.    -   Network Management Mechanism—In addition to SNMP, running as an        NT service provides an additional simple network management        capability by using a remote SvrMgr utility provided on all NT        servers to monitor and start/stop intelligent messaging network        services running anywhere on the network.    -   Startup Dependencies—An NT service can depend on the presence of        other services before it is allowed to start (e.g. some        intelligent messaging network servers depend on the fact that an        SQL database server is running as well as possible        server-to-server dependencies).

E. A Mechanism for Providing Discovery Services For Servers DuringStartup Sequence

The intelligent messaging network can include various servers including,e.g., the following:

-   -   1. PGs 116;    -   2. MRs 124; and    -   3. BESs 122.        The simplest instance of an intelligent messaging network can        include a server of each of the three types coupled together as        depicted in the exemplary embodiment of FIG. 1B.

FIG. 1B depicts, in an exemplary embodiment, a high level block diagram136 of the present invention including, e.g., one or more PGs 116 a-ccoupled to one or more MRs 124 a-c, which are in turn, coupled to one ormore BESs 122 a-c.

Each server-to-server connection can include a TCP connection. Asindicated in block diagram 136, PGs 116 a-c can be coupled to MRs 124a-c; MRs 124 a-c can be coupled to PGs 116 a-c and BESs 122 a-c (orHBESs 132 a-c); and BESs 122 a-c (or HBESs 132 a-c) can be coupled toMRs 124 a-c. Server startup logic can include, e.g., starting theservers 116, 122, and 124 in any order as each server can attempt tofind the server(s) of the required type to which it is to be coupled.The server start sequence, in an exemplary embodiment, can proceed asfollows:

-   -   1. Upon start-up, an intelligent messaging network server 116,        122 and 124 can create a TCP “listener” socket. The TCP listener        socket accepts connection requests from other intelligent        messaging network servers 116, 122 and 124.    -   2. The intelligent messaging network server then registers the        following information about the server in the intelligent        messaging network MR database 128:        -   The IP address of the server and the port that the server is            listening on for new connections;        -   The server's intelligent messaging network Domain; and            -   An intelligent messaging network Domain is a text string                (e.g. “MyTestDomain”) that allows multiple intelligent                messaging networks to run on the same physical network                without interfering with each other. An intelligent                messaging network server can only connect to other                intelligent messaging network servers in the same                domain.        -   The server's server type e.g.: PG 116, MR 124, or BES 122.    -   3. After the server registers itself in the MR database 128, the        registering server can obtain a unique database registration        identifier (ID) and then can search the MR database 128 for        other registered servers in the server's intelligent messaging        network domain and of the appropriate type; e.g., PGs 116 can        search for MRs 124 in their domain, MRs 124 can search for PGs        116 and BESs 122, BESs 122 can search for MRs 124.    -   4. In the simplest intelligent messaging network, each server        116, 122 and 124 can ford one instance of each peer type to        which it connects. However, the intelligent messaging network        can allow multiple servers of each type to run within a domain        in order to improve performance and redundancy. For example, in        an exemplary embodiment, if there are 2 PGs 116 and 3 MRs 124,        each PG 116 can be coupled to each of the MRs 124. For each peer        server it fords in the database 128, the intelligent messaging        network server can attempt to couple itself to that server on        the peer server's TCP listener socket.    -   5. If the intelligent messaging network server 116, 122 and 124        successfully connects to a peer, establishing a TCP connection,        the two coupled servers can then perform an intelligent        messaging network “connection handshake” in order to verify the        validity of the connection. The connection handshake can include        the following sequence:        -   a) The connecting server can send an intelligent messaging            network ServerConnect message to the peer server. This            message can contain the connecting server's unique database            registration ID (obtained when the server first registered            in the database, see step 2 above). The connecting server            can then wait a specified amount of time for a reply from            the peer server.        -   b) The peer server can receive the intelligent messaging            network “connection message” and can verify that the version            included as part of the intelligent messaging network            message is compatible with its own communications version            and that the message is indeed an intelligent messaging            network connection message. If the version is incorrect or            the message is not a connection message, the peer server can            terminate the TCP connection. If the peer server accepts the            connection message it can send an intelligent messaging            network connection message back to the connector in reply.        -   c) When the connecting server receives a “connection reply            message” the connecting server can also verify the message            version and type and can either keep the connection open, or            close the connection if, e.g., the version and type            verification fail.        -   d) If the connecting server does not receive an intelligent            messaging network connection reply message within the            specified time window, the connecting server can assume that            the peer server is, e.g., not a valid intelligent messaging            network server, or is functioning improperly and so it can            close the TCP connection to the peer server.

FIG. 1C is described below after FIG. 1F relating to MR 124.

PG Startup Sequence

FIG. 1D depicts a block diagram 144 illustrating an exemplary embodimentof discovery services message flow for a PG 116 startup sequence. Thediscovery service flow can begin with step 146.

In step 146, the PG 116 can use registration services provided by, e.g.,the intelligent messaging network server SDK to register the PG 116 withthe intelligent messaging network by adding an entry to aRegisteredServers table in the MR database 128.

From step 146 flow can continue with step 148.

In step 148, the PG 116 can use registration services provided by theintelligent messaging network server SDK to enumerate the list of allthe MRs 124 registered with the intelligent messaging network in, e.g.,the same domain. From step 148, flow can continue with step 150.

In step 150, using an IP address and listener port for each of the MRs124, the PG 116 can use communication services provided by theintelligent messaging network server SDK to establish and manage aTCP/IP connection with each of the MRs 124 contained in the enumeratedlist. When a PG 116 couples itself to the MR 124, the MR 124 can add thePG 116 to its RegisteredServers cache and can begin to start forwardingmessages to the PG 116. If a connection attempt fails, the PG 116 canre-attempt to connect to the MR 124, according to an exemplaryembodiment of the present invention.

MR Startup Sequence

FIG. 1E depicts a block diagram 152 illustrating an exemplary embodimentof discovery services message flow for a MR 124 startup sequence. Thediscovery service flow can begin with step 154.

In step 154, the MR 124 can use registration services provided by theintelligent messaging network server SDK to register itself with theintelligent messaging network by adding an entry to theRegisteredServers table in the MR database 128. It will be apparent tothose skilled in the art that an alternative database could be used.From step 154, diagram 152 can continue with step 156.

In step 156, the MR 124 can use registration services provided by theintelligent messaging network server SDK to enumerate a list of, e.g.,all PGs 116 and BESs 122 registered with the intelligent messagingnetwork. From step 156, diagram 152 can continue with step 158.

In step 158, using the IP Address and listener port for each PG 116, theMR 124 can use communication services provided by the intelligentmessaging network server SDK to establish and manage a TCP/IP connectionwith, e.g., each PG 116 contained in the enumerated list. When a MR 124couples to a PG 116, the PG 116 can add the MR 124 to its ServerConnections cache and can begin to start forwarding messages to theMessage Router. From step 158, diagram 152 can continue with step 160.

In step 160, using the IP address and listener port for each BES 122,the MR 124 can uses communication services provided by the intelligentmessaging network server SDK to establish and manage a TCP/IP connectionwith each BES 122 contained in the enumerated list. When a MR 124couples to a BES 122, the BES 122 can add the MR 124 to its ServerConnections cache and can begin to start forwarding messages to the MR124.

BES Startup Sequence

FIG. 1F depicts a block diagram 162 illustrating an exemplary embodimentof discovery services message flow for a BES 122 startup sequence. Thediscovery service flow can begin with step 164.

In step 164, the BES 122 can use the registration services provided bythe intelligent messaging network server SDK to register itself with theintelligent messaging network by adding an entry to theRegisteredServers table in the MR database 128. From step 164, diagram162 can continue with step 166.

In step 166, the BES 122 can use registration services provided by theintelligent messaging network server SDK to enumerate the list of, e.g.,all MRs 124 registered with the intelligent messaging network. From step166, diagram 162 can continue with step 168.

In step 168, using the IP address and listener port for each MR 124, theBES 122 can use the communication services provided by the intelligentmessaging network server SDK to establish and manage a TCP/IP connectionwith each MR 124 contained in the enumerated list. When a BES 122 cancouple to a MR 124, the MR 124 can add the BES 122 to itsRegisteredServers cache and can begin to start forwarding messages tothe BES 122. If the connection attempt fails, the BES 122 can reattemptto connect to the MR 124.

F. Server Connection Race Condition Handling

If two peer intelligent messaging network servers are started atapproximately the same time, it is possible that each will attempt toconnect to the other, thus establishing two connections between themrather than a desired single connection. The possibility of collidingconnection requests is the reason that during the connection handshake,the servers exchange unique database registration IDs. Each server canuse the unique database registration ID to keep track of which serversit is already connected to, so that if server A establishes a connectionto server B, and due to race conditions server B immediately establishesanother connection to server A, server A can use the unique databaseregistration ID passed by server B to realize that it already has aconnection to server B and thus can drop the new connection.

G. Server Registration Service

When an intelligent messaging network server is started, it can registeritself with the network by adding an entry to a RegisteredServers tablein the intelligent messaging network MR database 128. This can enableother intelligent messaging network servers to locate one another on thenetwork. An API provided by the intelligent messaging network server SDKcan allow for registering the following server attributes in theintelligent messaging network MR database 128:

-   -   Server Class—PG 116, BES 122, and MR 124;    -   Server Type—PGs 116 types can include CDPD, Mobitex and ISP        dialup. BES 122 types can depend on the server application;    -   Packet Header Version—can indicates the version of the packet        header that the all server supports; and    -   IP Address and Listener Port—can indicate the IP address and the        listener port number to be connected to by other servers in        order to communicate with this server.

H. Server De-Registration Service

When an intelligent messaging network server is stopped, it cande-register itself from the network by removing its entry from theRegisterServers table in the intelligent messaging network MR database128. An API can be provided by the intelligent messaging network serverSDK to de-register a server in the intelligent messaging network MRdatabase 128.

I. Server-to-Server TCP/IP Communications Service

In an exemplary embodiment of the invention, intelligent messagingnetwork servers can communicate with each other over a TCP/IP socketconnection. APIs provided by the intelligent messaging network servercan encapsulate the creation, management, and sending/receiving of dataover the socket connection.

II. Server-Specific Services

In addition to the above-described common set of services, each servercan also provide additional services that can be specific to thefunctionality of the server. Thus, in an exemplary embodiment, theintelligent messaging network architecture can include various coresoftware components that can run on, e.g.:

PG 116;

MR 124;

BES 122;

HTTP Proxy Back End Server 132; and

SNMP Management Console 130.

A. Protocol Gateway PGs Operation and Services

Using the registration services provided by the intelligent messagingnetwork server SDK, the PGs 116 can follow a predefined start upsequence to register itself with the intelligent messaging network. EachPG 116 can add an entry to the RegisteredServers table in theintelligent messaging network MR database 128 and can enumerate the listof all MRs 124 registered with the network in the same domain. Based onthe IP address and listener socket for each MR 124, the PG 116 canestablish and manage a TCP/IP connection with each MR 124 contained inthe enumerated list. When a PG 116 connects to an MR 124, the MR 124 canadd the PG 116 to its RegisteredServers cache and can begin forwardingmessages to the PG 116. If, however, the connection attempt fails (e.g.,there is a timeout), the PG 116 can re-attempt to connect to the MR 124after a configurable time period.

In addition to the above-described common services, the PGs 116 can beresponsible for supporting the following specific services:

1. Encapsulate the Network Communications Protocol

Each PG 116 can encapsulate the underlying wireless network accessprotocol so that it is transparent to MR 124 and BESs 122. As a result,when the MR 124 receives a message from a PG 116, it is unaware of theunderlying network access protocol used for communicating the message.

2. Message Segmentation

All messages to be transmitted over the network that exceed a predefinedsegment size can be segmented into multiple message segments.

3. Message Re-Assembly

All incoming message segments (except the last segment to complete themessage) received (including duplicate segments) can be immediatelyacknowledged back to the peer wireless protocol layer and can be queuedpending receipt of all message segments via an inbound message map. Whenthe last segment to complete the message is received, the PG 116 doesnot immediately send an acknowledgment to the peer wireless protocollayer. Instead, the message segments can be assembled into a completemessage, which can be forwarded to an appropriate BES 122 via an MR 124.When the BES 122 successfully receives the message and acknowledges thesame to the PG 116 via MR 124, then the PG 116 can acknowledge the lastsegment received thus completing the acknowledgment of the entiremessage. An inbound message map can manage a separate inbound messagemap for each unique link station ID of a sender.

4. Message Segment Duplication Detection

When a message segment has been received for a segmented message, the PG116 can check to make sure the message segment has not been alreadyreceived (i.e., a duplicate message segment). If the message segment isa duplicate, the segment can be acknowledged to the peer wirelessprotocol layer, discarded and conditionally logged.

5. Message Duplication Detection

When all message segments have been received for a message, the segmentscan be assembled into a complete message. If the message ID of theassembled message has been already received (duplicate message), thenthe message can be acknowledged to a corresponding peer wirelessprotocol layer, discarded and conditionally logged. Each PG 116 can keeptrack of the last n message IDs received for each unique link stationID.

6. Message Pacing/Message Retries/Message Time Outs

Any message that is bound for a client device 112 can be segmented intoa number of segments greater than a segmented pacing threshold and canbe sent at a pacing interval. The threshold and interval can beconfigurable prior to a gateway protocol startup. Each PG 116 canautomatically retransmit any message segment transmitted over thenetwork that is not acknowledged by a corresponding peer wirelessprotocol layer within a configurable amount of time. The PG 116 canretry a configured number of times before notifying a BES 122 that themessage could not be delivered to a client application.

7. Forwarding of Ack/Nack Messages

When a message segment is transmitted over the network 212, each PG 116can retain knowledge of all outstanding message segments pendingacknowledgment (message segments that have not been acknowledged by thepeer wireless protocol layer) via a pending acknowledgment map. Thepending acknowledgment map can maintain information pertaining tomessage segments that have been successfully transmitted and are pendingacknowledgment from the peer wireless protocol layer. If anacknowledgment (positive or negative) is received for a message segmentthat is not pending acknowledgment, the segment can be discarded andconditionally logged.

When all message segments have been positively acknowledged by the peerwireless protocol layer, the PG 116 can sen, as shown in step 5 of FIG.7, an ACK control message to the BES 122 via MR 124 (provided that theBES 122 has requested such notification) to indicate the message hasbeen successfully delivered to the client application. If the number oftransmission attempts for the message segment exceeds a configurablenumber of retry attempts, the PG 116 can send an NACK control message tothe BES 122 to indicate that the message could not be delivered to theclient application.

B. Message Router MR Operation and Services

Each MR 124 can communicate with the PGs 116 and BESs 122. Upon startup, the MR 124 can use the registration services provided by theintelligent messaging network server SDK to register the MR 124 itselfwith the intelligent messaging network by adding an entry to theRegisteredServers table in the MR database 128. The MR 124 can also usethe registration services to enumerate the list of all the PGs 116 andBESs 122 that are registered with the intelligent messaging network.Using the IP address and listener port or socket for each PG 116, the MR124 can establish and manage a TCP/IP connection with each PG 116contained in the enumerated list. When an MR 124 connects to a PG 116,the PG 116 can add the MR 124 to its Server Connections cache and canbegin to start forwarding messages to the MR 124. Based on the IPaddress and listener port for each BES 122, the MR 124 can alsoestablish and manage a TCP/IP connection with each BES 122 contained inthe enumerated list. See FIG. 1C. When a MR 124 connects to a BES 122,the BES 122 can also add the MR 124 to its Server Connections cache andcan begin to start forwarding messages to the MR 124.

Each MR 124 can also use the registration services provided by theintelligent messaging network server SDK to de-register itself from theintelligent messaging network by removing its entry from theRegisteredServers table in the MR database 128. The MR 124 can close theTCP/IP connection with each PG 116. Each PG 116 can also remove the MR124 from its Server Connections cache and can immediately stopforwarding messages to the terminating MR 124. Then, the MR 124 canclean up any previously allocated resources and can terminate.

FIG. 1C depicts an exemplary embodiment illustrating messaging routingaccording to the present invention. FIG. 1C illustrates a client user102 using a client device 112 can attempt to communicate via wirelessnetwork 108 and network 114 to resources coupled to PG 116. As shown,BESs 122 a, 122 b and 122 c can have already registered upon boot withMRDB 128 of MR 124. Advantageously, according to the present invention,routing can be based on content instead of address. Registration ordiscovery can include a providing server identifier (ID), a servicetype, and a message type supported by the particular BES 122. MR 124 canload into the cache of MR 124, the registration information about BESs122.

MRs 124 and BESs 122 can communicate via a TCP/IP connection. As shown,BES 122 a can be registered for service type 7 and message type 5. BES122 b can be registered for service type 7 and all message types asillustrated by an asterisk (*) wildcard character. Each BES can have aunique server ID and service type combination. The only server ID thatcan be shared is 0 (zero).

The client device 112 can communicate with PG 116 and can send a messageincluding a unique message key. The unique message key can include, inan exemplary embodiment, a server identifier (ID), a service type and amessage type, as shown. The PG 116 can provide the MR 124 the messageover network 118 b.

PG 116, in an exemplary embodiment, can route to a least recently usedMR 124, providing a round-robin load balancing function. In an exemplaryembodiment, redundancy can be provided by using, e.g., multiple PGs 116and multiple MRs 124. Similarly, when an MR 124 has a message to routeto a PG, in the case of an alert or a response, the MR 124 can similarlyuse a round-robin load balancing method to route the message to a leastrecently used PG 116 supporting the protocol of the client device 112associated with the message.

Also, MR 124 can route a message received from the PG 116, to a BES 122or HBES 132. MR 124 can route the message, in an exemplary embodiment,according to a set of semantic rules. In an exemplary embodiment, themessage can be routed to the BES 122 which most specifically correspondsto the contents of the message key. In an exemplary embodiment if morethan one BES 122 corresponds specifically to the message key, the leastrecently used BES 122 can be used by checking a time stamp identifyingthe last access to the BES 122.

As an illustrative example, suppose client device 112 sends a messagecontaining a message key {server ID=0; service type=7; and messagetype=5} to a BES 122. In the exemplary illustration, PG 116 wouldforward the message to the least recently used MR 124. MR 124 could lookat the message key {0, 7, 5} to determine how to route the message.Based on the example registrations described above for BES 122 a {0, 7,5}; BES 122 b {0, 7, *}; and BES 122 c {1, 7, *}, MR 124 could route themessage to BES 122 a since the BES 122 a most specifically correspondedto the message key by having the exact service type and message type asthe message key. It is important to note that BES 122 b with a wild cardasterisk for supported message type could also support the message ifBES 122 a was not available. The semantic rules could use the BES 122 bas an alternative routing destination, if BES 122 c is unavailable.

For purposes of sending follow-on messages to a particular BES 122, inan exemplary embodiment, a specific server ID can be placed in amessage. In an exemplary embodiment, only one BES 122 will have aspecific combination of server ID and service type.

In addition to the common services that all intelligent messagingnetwork servers support, the MRs 124 are responsible for supporting thefollowing specific services:

1. MR Message Authentication Service

The MR 124 can be responsible for determining that the sender of amessage is an authorized customer of the intelligent messaging network.When the source of a message is a client device 112, the MR 124 can usethe device's source address (e.g., IP address or Mobitex MAN number) ofthe client device 112 as the means of identifying authorized access.

When each MR 124 receives a client message, it can check the deviceaddress against a local cache of authorized devices 112. If the sourceaddress is not found locally, the MR 124 can then check the MR DB 128.If the device address is an authorized client device 112, in anexemplary embodiment, and the customer has permission rights to therequested service type, and the requested service type is not in use bythe customer's account with a different source address, the MR 124 cancache the device address, customer identifier, and requested servicetype to ensure fast authentication of additional messages from the samesource. Then, the message can be considered authentic and can beforwarded to the proper BES 122. Each MR 124 also can pass the customeridentifier to the BES 122 to use as a key to search for customerspecific information.

In order to support dial-up access, in an exemplary embodiment, messageauthentication based on the device's source address is not used, becauseduring a dial-up access, the source address that can be seen by an MR124 is the IP Address of the ISP provider. Each subscriber that desireswire-line access can have a User ID and Password, which can be selectedby the subscriber at the time they subscribe to a service, and can besaved as part of the MR DB 128.

Each MR 124 can initially follow the same procedure to authenticate adial-up message as it does when authenticating a wireless message.However, in case a message is received from a dial-up connection, the MR124 can issue an authentication challenge to the message source. Onreceiving the challenge, the client application can prompt the user 102to enter the user ID and password of the user 102, which can beforwarded (encrypted) to the MR 124 as an authentication request and canproceed with authentication process.

Once a message source has been authenticated, the MR 124 can check theservice type and source address of subsequent messages against itsauthentication cache and can allow/disallow the message as appropriate.Preferably, in an exemplary embodiment, the MR 124 does not keep thecached mapping between a source address and valid customer indefinitely.A configurable timeout period may be specified, after which cachedentries can be removed. The timeout interval can be the length of timethat has passed between successive messages from a cached client device112. When a client device 112 times out due to inactivity, the MR 124can remove it from its cache. For dial-up devices, the MR 124 can alsodecrement a device's authentication count within the intelligentmessaging network MR database 128. The authentication count can indicatehow many other MRs 124 have heard from the client device 112. When adial-up device's authentication count drops to zero, the device addresscan be removed from the MR DB 128.

2. MR client Message Routing Service

According to an exemplary embodiment of the invention, there can beseveral ways in which an MR 124 can route a client message to a BES 122,including, e.g.:

Indirect Routing—via an indirect routing table that can map message keys(service type and message ID) to a registered BES 122 that supports themessage key; and

Direct Routing—via targeting messages at a specific BES 122.

The form of routing can be determined based on the contents of anintelligent messaging message header. The intelligent messaging messageheader or message key can be pre-fixed to every application message.

The intelligent messaging message header can contain the followingfields, e.g.:

a 1-byte Server ID that can identify a specific server of the givenservice type. The value 0 can be reserved to indicate that indirectrouting is desired. A non-zero value can indicate that the message isdirected at a specific BES 122;

a 12-bit Service Type Identifier, which can be used by both indirect anddirect routing, can identify the type of service (e.g., MarketClip, FX,etc.) associated with the messages; and

a 12-bit Message Type Identifier that can uniquely identify the messagewithin the context of the specified service type required for directmuting.

a. Indirect Routing

When an MR 124 receives an incoming message from a client application,it can check the Server ID field contained in the intelligent messagingmessage header portion of the message. If the Server ID field of theintelligent messaging message header is zero, the MR 124 can route themessage to the proper BES 122 by consulting a routing table that can mapmessage keys (Service Type and Message ID) to the IP address of one ormore connected BESs 122 a-c as described above with reference to FIG.1C.

During server registration, all BESs 122 can be required to register alist of supported message keys. To minimize the number of entries thatare made in the routing table, if a given BES 122 supports the majorityof messages for a specific Service Type, it need only register a singleroot message key including only the Service Type. The small subset ofservice messages not supported by that BES 122 would be registered asindividual message keys by a different BES 122 of the same Service Type.The MR 124 can route messages based on the most specific key value(Service Type, Server ID, and Message ID) found in the table. If nospecific mapping is found, the MR 124 can use the Service Type portionof the key to look for root message entries. If the MR 124 locates morethan one BES 122 that satisfies the message key match, it can use around-robin scheduling procedure to pick which target BES 122 to routeto. For example, the timestamp of last access of the BES can beconsulted to determine a least recently used BES 122.

Consider, e.g., two third party services, MarketClip and FX, Reuters®news service solutions for real-time reporting on equities and foreignexchanges, with messages for each application supported by acorresponding BES 122. Under the configuration of the invention, eachapplication BES 122 could only have to register its root service type(e.g., MktMon or FX) in order for its messages or responses for clientdevices 112 to be routed correctly by the MR 124. Suppose that two BESs122 currently support news requests independently of one another (i.e.there is no common news BES 122 that both of them use), but a separatenews BES 122 can be created to handle ALL news requests. Ideally, no newsoftware should be sent to service providers so that all future newsmessages (for either application) are tagged to go to the new newsserver. Rather, the new news BES 122, upon registration, can add thespecific news message keys previously handled by the MarketClip and FXBESs 122 to the MRs 124 message routing table.

It should be noted that the original BESs 122 do not need to changebecause the news BES 122 message keys can contain the service types andmessage IDs specific to the two applications. Each MR 124 can do itsprimary muting based on the more specific table entries, the same newsmessages that would have formerly been muted to the two BESs 122, couldget routed to the new news BES 122. Thus, the BESs 122 can be designedaround specific services, rather than a suite of services that comprisean application, some of which may be common to other applications. Underthis arrangement, overall response performance can improve as specificservices are assigned to their own BES 122. This is because a clientapplication not using a given service does not have to wait, while theBES 122 is accessing process requests for a different service.

b. Direct Routing

BESs 122 that can maintain state information about a particular clientdevice 112 can often require direct routing. For a client to ensure thata message reaches a specific BES 122, the intelligent messaging networkmessage header portion of the message can contain a non-zero value inthe Server ID field. When an MR 124 sees a non-zero value in the ServerID field, it can route the message to the proper BES 122 by consulting arouting table that maps server keys {Service Type, Message ID, ServerID} to the IP address of a connected BES 122.

Specifying a Server ID alone can be not sufficient to ensure that themessage is delivered to the proper BES 122. Even when using directrouting, a BES 122 can register the service types and message IDs it canhandle; and the service type/message ID of a direct route message canmatch those types registered by the BES 122 with the specified ServerID. Management of BES 122 IDs can be the responsibility of theapplication: If an application runs more than one BES 122 with the sameServer ID, then messages with that Server ID can be routed to the BES122 whose message routing table can contain the most specific match withthe messages service type and Message ID. If two BESs 122 can map thesame Server ID, Service Type, and Message ID, then, as in indirectrouting, the MR 124 can use round robin scheduling to pick a target BES122.

A BES 122 may use both direct and indirect routing on an as neededbasis. To illustrate this, consider a BES 122 that for the most part isstateless, but has one or two logical operations that can requireseveral targeted client/server messages to complete. If the BES 122 caninitiate an operation that can require a targeted response, it can placeits Server ID in the intelligent messaging network message headerportion of the message it sends to the client application. When theclient application responds, it uses the same Server ID in the responsemessage to assure that the response is sent to the original Server. Allother “stateless” messages can be sent with a Server ID of 0, so thatthey can be indirectly routed.

3. MR Back-End Server BES Message Routing Service

BES 122 messages sent to a client application can pass through the MR124. Each MR 124 can decide which PG 116 to which to forward themessage. The MR 124 can choose the proper PG 116 based on, e.g., thecommunications type (e.g., CDPD, Mobitex, ISP Dialup, etc.) used by asubscriber's service provider. The mapping of communication type toclient device address can be maintained by the MR 124 based on fixedentries in the MR DB 128 that can map source address of a client device112 or used ID and password to a specific communication type. Each PG116 can also indicate the communication type of the PG 116 during theserver registration process. If a PG 116 could not deliver a message tothe client application, the PG 116 can send a network controlnon-acknowledgement (NACK) message to the BES 122 that originated themessage, indicating that the message could not be delivered.

4. Send Via clientDeviceInfo

When a BES 122 sends a message to a client application in response to areceived request message, the client device address (referred to, as itsclientDeviceInfo), which is a part of the received request message, canbe known to the BES 122. In response, the BES 122 can provide theclientDeviceInfo as part of the AIMSvrPacket sent to the MR 124.Consequently, the MR 124 can then simply pass this information to theappropriate PG 116, which can then send the message to that clientdevice 112 address.

5. Send Via CustomerID

At times, a BES 122 may need to asynchronously send a message to asubscriber (e.g. MarketClip Alert). Since this message is not inresponse to an incoming client message, the clientDeviceInfo may not bereadily available to the BES 122. Rather than forcing the BES 122 tokeep a mapping between client identifiers and their LinkStationIDs, aBES 122 may send a message to a client based solely on the customer ID.In this case, the AIMSvrPacket sent to a MR 124 contains a NULLLinkStationID and a valid client ID. The receiving MR 124 can searchit's authenticated device cache for an active device associated with thespecified client ID and then can use the device's LinkStationID toforward the message to an appropriate PG 116.

C. Back-End Server BES Operation and Services

A BES 122 is an application specific server that can implement logic toprocess messages specific for that type of server. For example, an FXBES 122 can handle requests related to foreign exchange functions. A BES122 can communicate directly with one or more MR 124 s. Typically, BESs122 can run behind the firewall 120. However, the intelligent messagingnetwork architecture cannot preclude BESs 122 from running outside thefirewall 120.

Excluding the application logic, which may be complex, the developmenteffort to implement a BES 122 can be relatively straightforward. Theintelligent messaging network Server SDK can encapsulate those functionsthat are common to all BES 122 s, thereby insulating developers from,e.g., details of transport control, compression, registering andde-registering with the MR DB 128.

Similar to other servers, the BESs 122 can use the registration servicesprovided by the intelligent messaging network server SDK to registerthemselves with the intelligent messaging network by adding an entry tothe RegisteredServers table in the MR DB 128. Each BES 122 can establisha TCP/IP connection with each registered MR 124, using a correspondingIP address. When a BES 122 connects to an MR 124, the MR 124 can add theBES 122 to its RegisteredServers cache and can begin to start forwardingmessages to the BES 122. When de-registering itself from the network,each of the BESs 122 remove its entry from the RegisteredServers tablesin the intelligent messaging network MR database 128. The BES 122 cannotify each MR 124 of its impending shutdown. This can allow each MR 124to remove the BES 122 from its RegisteredServers cache and canimmediately stop forwarding messages to the terminating BES 122.

In addition to the common services, the BESs 122 can be responsible forsupporting the following specific functions:

1. Application Protocol Aware Service

From the perspective of the BES 122, the BES 122 can directly with aclient application. In reality; however, a BES 122 can communicate withone or more MRs 124. In the intelligent messaging network architecture,only the BESs 122 can have knowledge of the application content requiredto communicate with a client application.

2. Extended Intelligent Messaging Network Compression

In the exemplary embodiment, intelligent messaging network can providean Adaptive-Huffman base compression service. The intelligent messagingnetwork architecture can provide the necessary hooks to enable 3^(rd)party OEM compression mechanisms. If a BES 122 has specific compressionrequirements for its application data that are not addressed byintelligent messaging network supplied compression services, (i.e.Adaptive-Huffman); the BES 122 can be responsible for providing thecompression mechanism.

3. Security Services

The architecture can provide the necessary hooks to enable 3^(rd) partyOEM security mechanisms. If a BES 122 has specific security requirementsfor its application data, the BES 122 can be responsible for providingthe security mechanism.

4. Forwarding of Ack/Nack Messages

When a client message is delivered to the BES 122, the BES 122 can senda network control acknowledgement (ACK) message to a PG 116 thatoriginally received the message. When the PG 116 receives the networkcontrol ACK message from the BES 122, it can send a transport level ACKmessage to the client device's peer wireless protocol layer indicatingthat the message was delivered successfully to the BES 122.

III. Intelligent Messaging Network MR Database

In an exemplary embodiment of the present invention, an intelligentmessaging network database can use an AIM Database available from AetherSystems of Owings Mills, Md., U.S.A. which, can maintain a common poolof information between intelligent messaging network servers. Thisinformation, which is independent of any specific messaging application,can be stored and accessed from a SQL database known as, e.g., the MR DB128, or the BES DB 126. In an exemplary embodiment, the MR DB 128 can beshared by all intelligent messaging network servers 116, 122, and 124.The following sections describe the tables that comprise the intelligentmessaging network MR database 128 schema. It will be apparent to thoseskilled in the art that the schema could also be used for anotherdatabase, such as, e.g.; BES DB 126.

1.1 Schema

1.1.1 ServiceTypes Table

The ServiceTypes table is a list of all the service types supported bythe intelligent messaging network.

ServiceTypes Table Column Name Type Description ServiceName varchar[30]Service Name TypeID int ID of the Service AllowMultiAccess bit True ifservice allows multiple device access from a single user, false if onlyallows single device access from single user concurrently1.1.2 RegisteredServers Table

The RegisteredServers table is used during the connection process andkeeps track of the location and type of all Servers currently running onthe Network. Access to this table is through the Server SDK.

RegisteredServers Table Column Name Type Description DbID long Unique DBID used for cross referencing ServiceName varchar[30] Server Name Classint Server Class e.g. FES (PG), BES, MR 124 etc SubClass int ServerSubclass e.g. CDPD, Mobitex, etc DeathCount int The number of timesconnecting Servers have failed to connect to the Server ServerId byteOptional ID used for Server-Specific Message Routing NetHdrVersion intNetwork header version supported by this Server. IP Address varchar[15]Network location of Server Port short Listener port Server monitors forconnection requests PortB short A second port the Server monitors Domainvarchar[20] Name of the Domain the Server is running in RegistrationFILETIME Date/Time when Server registered Time1.1.3 ServerMsgMap Table

The ServerMsgMap is accessed during Server Registration, MR 124 Start-UPand client Message Routing. This table maps a running Server to the setof Message's that should be routed to that Server. Access to this tableis through Intelligent messaging network Server SDK.

ServerMsgMap Table Column Name Type Description ServerDBID long Crossreference to DBID column in RegisteredServer Table ServiceType int Typeof Service message handled by this Server MessageID int MessageIdentifier of message handled by this Server ServerID byte Optional IDused for Server-Specific Message Routing1.1.4 AuthorizedUsers Table

The AuthorizedUsers table is accessed during Message authentication. Thetable contains a list of UserIDs/Passwords with authorized access to theintelligent messaging network Network. Access to this table is throughthe Server SDK.

AuthorizedUsers Table Column Name Type Description UserID varchar[25]Identifier chosen by the customer e.g. (rudy, RudyB etc). This is thelogin ID for ISP dial-up service. Password varchar[25] Customer PasswordAccountNo char[8] Customer Account Identifier CustomerID long UniqueCustomerID used for cross referencing

The AuthorizedDevices table is accessed during message authentication.This table contains a list of device addresses with authorized access tothe intelligent messaging network Network. Entries may be permanent (aMobile client Device) or temporary (a Wire-line device). Access to thistable is through the intelligent messaging network Server.

AuthorizedDevices Table Column Name Type Description DevAddressvarchar[25] Mobile client device address (IP, MAN, etc) Wireline bit 0 =Mobile client, 1 = Wire-line CommType int Communication Type (CDPD,Mobitex, CDMA, etc) of the client device Authentication int No. of MRs124 currently aware of Count this device AccessFlag int Used to blockaccess for devices reported missing or stolen CustomerID long Crossreference to Customer ID in AuthenticatedUsers table Token long Tokenused for security with wireline devices1.1.6 UserRights Table

The UserRights table is accessed during message authentication. Thistable contains the service types an authorized user can access. Accessto this table is through the Server SDK.

UserRights Table Column Name Type Description CustomerID long Crossreference to CustomerID in AuthenticatedUsers table. ServiceType intService Type the Customer is authorized to use. Cross reference toTypeID in ServiceType table.1.1.7 ActiveUsers Table

The ActiveUsers table is accessed during message authentication. Thistable contains the list of active customer IDs and the services they areusing with a count of MRs 124 that have authenticated the account forthe service in use. The purpose of the table is to detect and preventmultiple devices from accessing a service with same customer II) whenthe AllowMultiAccess bit is “false.” Also, the table contains theLinkStationType and LinkStationID used by the customer so the MRs 124can support NULL LinkStationID from the BES 122. Access to this tablecan be through the intelligent messaging network server.

ActiveUsers Table Column Name Type Description CustomerID long Crossreference to CustomerID in AuthenticatedUsers table. ServiceType intService type in use by Account No MRCount byte Number of MRs 124 thathave authen- ticated the account for the service in use CommTypesmallint Communication Type (CDPD, Mobitex, etc) of the client deviceLinkStationID varchar[25] IP/Port or Mobitex Address1.1.8 Comm Types Table

The CommTypes table is a list of all communication Protocols supportedby the intelligent messaging network.

CommTypes Table Column Name Type Description CommName varchar[25] Nameof the communication Protocol TypeID smallint Communication Type ID1.2 Stored SQL Procedures

SQL procedures are used to manage the database. The following is a listof definitions commonly used as parameters in the stored SQL procedures.

CustomerID—The customer's unique identifier.

UserId—The user Id is used to authenticate ISP dial-up access.

Password—The password is used to authenticate dial-up access.

AccountNo—The account number can be both alpha and/or numeric and is forcustomer service purposes.

ServiceType—The service type the customer is provisioned to access. Forexample, MarketClip, MarketTrader, etc.

DeviceAddress—For CDPD devices, this is an IP address in dot notation.For Mobitex, this is a MAN number.

CommType—The type of Network Protocol the client device is using toaccess the intelligent messaging network Network. For example, CDPD,Mobitex, CDMA.

DeviceType—The type of access to the intelligent messaging networkNetwork, either wireless or wireline.

NotifyAMR—True to notify all MRs 124 and false to not notify.

ReturnCode—The return code from the stored procedure.

1.2.1 NewCustomer

This stored SQL procedure allows customer service to enter a newcustomer using a wireless CDPD device to the database. User Id andPassword are entered as NULL.

Input:

UserID (varchar[25])

Password (varchar[25])

DeviceAddress (varchar[25])

AccountNo (char[3])

ServiceType (int)

Output:

CustomerID (int)

ReturnCocle (int)−0=Success, 1=Duplicate User ID, 2=Duplicate deviceaddress.

1.2.2 DeleteCustomer

This stored SQL procedure allows customer service to delete a customerfrom the database. This procedure also deletes any devices used by thecustomer and services provisioned for the customer.

Input:

CustomerID (int)

Output:

ReturnCode (int)−0=Success, 1=Invalid customer id.

1.2.3 AddUser

This stored SQL procedure allows customer service to add a user id andpassword to the database.

Input:

UserId (varchar[25])

Password (varchar[25])

AccountNo (char[8])

Output:

CustomerID (int)

ReturnCode (int)−0=Success, 1=Duplicate user id.

1.2.4 DeleteUser

This stored SQL procedure allows customer service to delete a customerfrom the database. This procedure also deletes any devices used by thecustomer and services provisioned for the customer.

Input:

CustomerID (int)

Output:

ReturnCode (int)−0=Success, 1=Invalid customer id.

1.2.5 Change Password

This stored SQL procedure allows customer service to change a user'spassword in the database.

Input:

UserID (varchar[25])

Password (varchar[25])

Output:

ReturnCode (int)−0=Success, 1=Invalid UserID

1.2.6 AddUserRight

This stored SQL procedure allows customer service to add a user accessright to a customer defined in the database.

Input:

CustomerID (int)

ServiceType (int)

Output:

ReturnCode (int)−0=Success, 1=Invalid customer id, 2=Duplicate entry

1.2.7 DeleteUserRight

This stored SQL procedure allows customer service to delete a useraccess right from a customer defined in the database.

Input:

CustomerID (int)

ServiceType (int)

Output:

-   -   ReturnCode (int)−0=Success, 1=Invalid customer id, 2=Invalid        user right for the customer.        1.2.8 AddDevice

This stored SQL procedure allows customer service to associate a deviceaddress to a defined customer in the database.

Input:

DeviceAddress (varchar[25])

Wireline (bit)−0=client, 1=wireline.

CommType (smallint)−1=CDPD, 2=Mobitex, 3=ISP Dial up

CustomerID (int)

Token (int)

Output:

-   -   ReturnCode (int)−0=Success, 1=Bad parameter, 2=Duplicate device        address, 3=invalid customer id, 4=Customer already has device        address.        1.2.9 DeleteDevice        This stored SQL procedure allows customer service to delete a        device address from a defined customer in the database.        Input:

DeviceAddress (varchar[25])

Output:

ReturnCode (int)−0=Success, 1=Device address not found

1.210 DeleteDeviceByCustID

This stored SQL procedure allows customer service to disassociate bydeletion of ALL device addresses from a defined customer in thedatabase.

Input:

CustomerID (int)

Output:

ReturnCode (int)−0=Success, 1=No device address(es) to delete.

1.2.11 SuspendUser

This stored SQL procedure allows customer service to suspend a user andall the user's device address' access to the intelligent messagingnetwork and notify all MRs 124 to remove the device address from it'slocal cache. This mechanism is used when a customer reports a lost orstolen client device.

Input:

CustomerID (int)

Output:

ReturnCode (int)−0=Success

1.2.12 ReactivateUser

This stored SQL procedure allows customer service to reactivate a userand all the user's device address' access to the intelligent messagingnetwork.

Input:

CustomerID (int)

Output:

ReturnCode (int)−0=Success.

1.2.13 SuspendDevice

This stored SQL procedure allows customer service to suspend a deviceaddress' access to the intelligent messaging network and notify all MRs124 to remove the device address from it's local cache.

Input:

DeviceAddress (varchar[25])

NotifyAMR 24 (bit)−True to suspend the device address from all MRs 124memory, false not to.

Output:

ReturnCode (int)−0=Success, 1=Error creating Server Manager, 2=Errorcalling Server Manager.

1.2.14 ReactivateDevice

This stored SQL procedure allows customer service to reactivate a deviceaddress' access to the intelligent messaging network.

Input:

DeviceAddress (varchar[25])

Output:

ReturnCode (int)−0=Success.

1.2.15 GetCustomerID

This stored SQL procedure allows customer service to get the customeridentifier associated with a device address.

Input:

DeviceAddress (varchar[25])

Output:

CustomerID (int)

ReturnCode (int)−0=Success, 1=Device address not found.

IV. HTTP Proxy Back End Server

Most industry standard browsers support the ability to be configured toaccess the Internet via a proxy server instead of communicating directlywith an HTTP Web Server. The Intelligent messaging network HTTP ProxyBack End Server 132 is responsible for handling incoming HTTP requests,sending the request over the Internet to the target Web HTTP Server, andtransmitting the response back to the client device. The Intelligentmessaging network HTTP Proxy Back End Server 132 supports variousversions of the HTTP protocol specification. The HTTP Proxy Back EndServer 132 is also responsible for communicating with a target HTTP WebServer. In order to handle each inbound HTTP request, the HTTP ProxyBack End Server 132 creates and manages a TCP/IP socket connection tothe target Web HTTP Server. When the HTTP Proxy Back End Server 132receives the response from the Web HTTP Server, it creates an HTTPresponse message and formats it for transmission back to the clientapplication running on a client device.

V. HTTP Redirector

Browsers 104 can typically communicate directly to an HTTP Web Servervia TCP/IP. TCP/IP, however, is a chatty LAN protocol requiringsignificant overhead that is not a cost effective way for browsing theInternet wirelessly. According to one embodiment of the invention, anHTTP Redirector 106 can intercept raw HTTP requests from the browser 104and can redirect the request over the intelligent messaging network forfulfillment by an HTTP Proxy Back End Server 132. When the HTTPRedirector receives a response from the HTTP Proxy Back End Server 132,it can simply pass the response to the browser 104 to process.

FIG. 2 illustrates a block diagram 200 of an exemplary embodiment of thepresent invention. Block diagram 200 illustrates an HTTP Redirector 106interacting with the browser 104 and intelligent messaging network. TheHTTP Redirector 106 can act as a “client side” proxy server allowing itto intercept Web browser HTTP requests. When communicating over thewireless network, the HTTP Redirector 106 can take advantage of theoptimized wireless protocol and compression services offered by theIntelligent messaging network and the protocol of the present invention.This results in significant byte savings when sending HTTP requests andreceiving HTTP responses over a wireless network. In the exemplaryembodiment, the HTTP Redirector can support browsers 104 such as, e.g.,Microsoft's Internet Explorer 4.0 and Netscape's Communicator 4.5browsers on the Windows 95, 98, NT, 2000 and Windows CE platforms.

As mentioned above, browsing the Internet using a standard version of aconventional browser 104 is not ideal in a wireless environment.Standard versions of browsers 104 send HTTP requests over TCP/IP, whichis a chatty LAN protocol. TCP/IP is not cost effective in terms ofbandwidth usage in a wireless environment. Furthermore, a standardversion of browser 104 can require an IP based network andconventionally does not work with non-IP based wireless networks such asMobitex. The redirector 106 can address these issues and can provide amethod of using a standard Web browser 104 in a wireless network.

Referring to FIG. 2, in an exemplary embodiment, browser 104 of a clientdevice 112 can typically allow access to resources such as, e.g., adestination Web server 210, such as an Internet server 142 a on anetwork 202, such as, e.g., the global Internet, through a Proxy IP/port204 instead of communicating directly with the destination Web server210. In the environment of the present invention, the Proxy IP/port 204can fulfill a request on behalf of the client device 112 to thedestination Web server 210. The redirector 106 can act as a“client-side” proxy. The HTTP Redirector 106 can sit on top of standardmobile libraries 208 provided by the intelligent messaging network.These mobile libraries 208 can be optimized for the specific wirelessprotocol supported by the specific client device 112 a-c.

The HTTP Redirector 106 can intercept all requests from browser 104. Theraw HTTP request can then be packaged into an intelligent messagingnetwork message and transmitted through the intelligent messagingnetwork 114 to the BES 122 a-c designed to handle HTTP requests.

The HTTP BES 132 can forward the request to a Web server of a contentprovider such as, e.g., destination web server 210, which can provide aresponse. The content provider can be a third party in an exemplaryembodiment. The communication to the content provider can occur via thenetwork 202 of FIG. 2. A network 212 depicted in FIG. 2 can include theintelligent messaging network of the present invention, e.g., theunderlying LAN network 118 a and b, the PGs 116, the firewall 120,router 110, and the MR 124.

When the HBES 132 receives the response from the destination Web server210, HBES 132, or BES 122 (not shown), can package the response into anintelligent messaging network message and can transmit the response backto the requesting client device 112 via the PG 116 via the MR 124.

When the message arrives at the client device 112, it can be passed upto the redirector 106 where the message can be unpacked from itsintelligent messaging network format into an HTTP response and can besent to the browser 104. The HTTP redirector 106 can maintain allconnections with the browser 104 throughout this process, so that fromthe perspective of the browser 104, the browser 104 appears to becommunicating directly to the Web server 210.

The mobile libraries 208 can be optimized for the underlying wirelessprotocol. The HTTP Redirector 106 can sit on top of the libraries 208providing the browser 104 with the same benefits without anymodifications to the browser 104. Since the HTTP Redirector 106 packagesHTTP requests and responses into intelligent messaging network messages,the raw payload of the messages can be compressed. Most conventional Webtraffic deals with straight text in the form of HTML, so the amount ofdata transmitted can be greatly reduced by using standard compressiontechniques. The compression techniques can result in an increase in datathroughput and a reduction of airtime.

In addition to compression, in an exemplary embodiment, performance canbe enhanced by the fact that TCP/IP is not used over the wirelessnetwork, where the SNTL transport protocol of the present invention israther used.

Turning briefly to FIG. 3, an exemplary embodiment of a networkcommunications layered architecture is depicted. FIG. 3 includes blockdiagram 300, which is described further below following the descriptionwith reference to FIG. 8A.

VI. Message Flow

The flow of any messages within the network can include authenticationby the MR 124 via authentication challenge success, failures, clientapplication request to BES 122, BES 122 response to client application,and BES 122 alert to client application.

FIG. 4 illustrates a flow diagram 400 depicting an exemplary embodimentof the present invention. Flow diagram 400 numerically depicts a flow ofmessages that corresponds to the authentication challenge success flow.Flow diagram 400 numerically shows message paths between a client device112 and an MR 124 including exemplary steps labeled by numbers 1-8, asfollows:

-   -   1. The client application can send an application request        message to the MR 124 (the PG 116 is not explicitly involved in        authentication), i.e., a device authentication;    -   2. The client application running on a client device may fail        the authentication of the MR 124;        -   There are several ways a client application running on a            client device can fail authentication. The MR 124 cannot            find the device address in its local cache or the            AuthorizedDevices table in the intelligent messaging network            MR database 128. The device's security token in the            LinkStationID is not the same as the device's security token            in the intelligent messaging network MR database 128. The            subscriber does not have user rights to the requested            service.    -   3. The MR 124 can send a negative acknowledgment (NACK) message        to the client application with the appropriate error code;    -   4. The client application can respond with an authentication        request message including an UserID, secure password, and the        requested service type to authenticate; i.e., reauthentication;    -   5. The MR 124 can check the UserID and password against the        AuthorizedUsers in the MR DB 128;        -   If the UserID/password are valid, the MR 124 can verify that            the subscriber has rights to the requested service. If the            subscriber does have user rights to the service, the MR 124            can add the device address to the AuthorizedDevices table,            as well as to the MR 124 local cache and can assign a            security token to the client application running on the            client device 112.    -   6. The MR 124 can send an authenticated response message with a        success value to the client application to let the client        application know that the client application has been        authenticated; the security token can also be sent to the client        device 112; i.e., an indication of success;    -   7. The client application can re-send the original message        (step 1) that caused the authentication challenge with the new        security token; i.e., send request; and    -   8. The MR 124 can verify the device address against the        authentication cache of the MR 124 and can forward the message        to the proper BES 122 or HBES 132 (not shown).

FIG. 5 illustrates a flow diagram 500 depicting an exemplary embodimentof the present invention. Flow diagram 400 numerically depicts a flow ofmessages that can correspond to the authentication challengesuccess/failure. The diagram numerically shows message paths between theclient device 112 and the MR 124 including exemplary steps labeled bynumbers 1-7, as follows:

-   -   1. Client application can send an application message to the MR        124 (again, the PG 116 is not explicitly involved in        authentication, in an exemplary embodiment, all client/MR 124        communications can pass through the PG 116); i.e., device        authentication;    -   2. The client device 112 can fail the MRs 124 authentication;        -   There are several ways a device can fail authentication. For            example, the MR 124 cannot find the device address in its            local cache or the AuthorizedDevices table in the            intelligent messaging network MR database 128. The security            token of the client device 112 in the LinkStationID can be            not the same as the device's security token in the            intelligent messaging network MR database 128. The user of            the client device 112 can not have user rights to the            requested service.    -   3. The MR 124 can send a negative acknowledgment (NACK) message        to the client application with the appropriate error code;    -   4. The client application can respond with an authentication        request including the UserID, secure password and the requested        service type to authenticate; i.e., logon with userid and        password;    -   5. The MR 124 can check the UserID and password against the        AuthorizedUsers in the MR DB 128; the UserID, password can be        invalid and/or the user can not have rights to the requested        service;    -   6. The MR 124 can send an authentication response message with a        failure value to the client application to let it know that the        authentication has failed; i.e., authentication failure; and    -   7. The client may choose to prompt the client user 102, e.g., to        re-enter the UserID and password and repeat the flow diagram 500        starting from step 4; i.e., retry.

FIG. 6A illustrates a flow diagram numerically depicting a flow ofmessages that corresponds to a client application request to BES 122.The diagram numerically shows message paths between the client device112 and the MR 124 including exemplary steps labeled by numbers 1-6, asfollows:

-   -   1. The client application that can be running on client device        112 can create an application request (APP REQ) message and can        pass the message to the transport layer to transmit over the        network 212;    -   2. The transport layer can determine if the message needs to be        segmented into multiple segments; the transport layer can        transmit the message over the network and can wait for a        transport level ACK;    -   3. Upon receiving the APP REQ message, the PG 116 can assemble        the message segment into a complete application message (if        necessary) and can send the application message to the next        available MR 124;        -   If no MR 124 is available, a NACK message can be generated            by the PG 116 and can be sent back to the client application            with the appropriate error code. Preferably, the PG 116 can            not immediately send a transport ACK message back to the            client application. This can be done when the BES 122            receives the application message and sends an ACK control            message back to the PG 116.    -   4. The MR 124 can look up the device address and the service        type (first in its local cache, then if necessary in the        intelligent messaging network MR DB 128) to see if the message        is from an authorized source;

If the message is from an authorized source, the MR 124 can choose thenext available BES 122 that has been registered to support the specifiedservice type and can then send the message to that BES 122. If there areno BESs 122 registered that can support the specified service type, aNACK message can be generated by the MR 124 and can be sent back to theclient application with the appropriate error code.

-   -   5. Upon receiving the application message from the MR 124, the        BES 122 can send an acknowledgement (ACK) control message back        to the PG 116 that received the application message; the BES 122        can also process the incoming message; and    -   6. Upon receiving the ACK control message from the BES 122, the        PG 116 can send a transport ACK message to the client        application at client device 112; in some exemplary embodiments,        sending ACK messages can be optional.

FIG. 6B depicts an exemplary embodiment of a message flow diagram 602illustrating transmission of a multi-segment message from a clientdevice 112 to a BES 122 according to the present invention. Flow diagram602 can begin with step 604.

In step 604, the simple network transport layer (SNTL) application cansegment the message into multiple segments, can encapsulate the segmentswith an SNTL segment header 900, and can transmit the message initiallyto PG 116. An exemplary embodiment of a message header 900 isillustrated below with reference to FIG. 9. As will be apparent to thoseskilled in the relevant art, due to a high bit error rate in wirelesscommunication links, it can be expected that not all transmissions to PG116 will be received from the client device 112. From step 604, the flowdiagram can continue with step 606.

In step 606, the PG 116 can send to client device 112 an acknowledgement(ACK) of receipt of the transmitted messages at the PG 116. As shown, inthe exemplary embodiment, receipt of only segment 1 is acknowledged.Receipt of segment 2 is not acknowledged. From step 606, the flowdiagram 602 can continue with step 608.

In step 608, in an exemplary embodiment, client device 112 canautomatically its retry, or retransmit segment 2 of the message to thePG 116, since acknowledgement was not received for segment 2 in step604. User datagram protocol (UDP) is an efficient communicationprotocol, however it is unreliable, lacking provision to segmentmessages and retransmit unacknowledged messages. In the exemplaryembodiment, the peer protocols of the SNTL layers on the client device112 and PG 116 can work in coordination with UDP to provide highlyoptimized and reliable wireless communication while using efficientconnectionless (i.e., unlike TCP) UDP communication. In an exemplaryembodiment, the SNTL layers can provide other useful transport functionssuch as, e.g., pacing, congestion control and other functionalitywithout requiring an entire TCP transport stack. The SNTL layer caninclude, in an exemplary embodiment, a 4 bytes wide header, 6 bytes widefor multi-segment messages, as discussed with reference to FIG. 9. Fromstep 608, flow diagram 602 can continue with step 610.

In step 610, PG 116 can transmit the complete multi-segment message toMR 124. From step 610, flow diagram 602 can continue with step 612.

In step 612, MR 124 can route the message to BES 122 as discussed abovewith reference to FIG. 1C. From step 612, flow diagram 602 can continuewith step 614.

In step 614, BES 122 can send an acknowledgement of receipt of themulti-segment message to MR 124. From step 614, flow diagram 602 cancontinue with step 616.

In step 616, MR 124 can send acknowledgement of receipt of themulti-segment message at the BES 122 on to PG 116. From step 616, flowdiagram 602 can continue with step 618.

-   -   In step 618, PG 116 can send acknowledgement of receipt of the        multi-segment message at the BES 122 on to client device 112. PG        116 can also send acknowledgment of receipt of segment 2 of the        message as well. In one exemplary embodiment acknowledgment of        receipt of the second segment can occur following step 606. From        step 618, flow diagram 602 can immediately complete.

FIG. 7A illustrates a flow diagram 700 of an exemplary embodiment of thepresent invention. Flow diagram 700 numerically depicts a flow ofmessages that corresponds to a response from BES 122 to a request of theclient application, illustrated and described further above withreference to FIG. 6A. Flow diagram 700 numerically shows message pathsbeginning from the BES 122, through the MR 124 and PG 116 to clientdevice 112 including exemplary steps labeled by numbers 1-5, as follows:

-   -   1. A BES 122 can respond to a client application request as        illustrated in flow diagram 600; the BES 122 can pass the        response message (REQ RESP), message flags, customer ID and        LinkStationID (cached from the previous incoming request) in        flow diagram 700, which can represent a second or so-called        “send” call;        -   Message flags can specify whether to compress and/or encrypt            the message and whether the BES 122 requires an ACK message            when the PG 116 has successfully delivered the application            message to the client application running on client device            112. The BES 122 can send the application message to the            next available MR 124. If no MR 124 is available, then a            false can be returned from the send.    -   2. The MR 124 can use the LinkStationID to determine the        associated communication type (e.g., CDPD, Mobitex, etc.) and        can send the message to the next available PG 116 of the correct        communication type;    -   3. The PG 116 can segment the application message (if necessary)        and can transmit the application message over the network;    -   4. The transport layer can receive the message segment and can        assemble the message segment into a complete application message        (if necessary); the transport layer can send a transport ACK        message to the PG 116 that sent the message; it is important to        note that, in some exemplary embodiments, sending ACK messages        can be optional; and    -   5. When the PG 116 receives the transport ACK from the client        application, the PG 116 can send an ACK control message back to        the BES 122 (via the MR 124) that was the source of the original        message (if required).

FIG. 7B depicts an exemplary embodiment of a message flow diagram 702illustrating transmission of a multi-segment message from BES 122 to aclient device 112 according to the present invention. Flow diagram 702can alternatively represent sending of a multi-segment alert from BES122 to a client device 112. Flow diagram 702 can begin with step 704.

In step 704, BES 122 can transmit a multi-segment message intended for aclient device 112 to MR 124: From step 704, flow diagram 702 cancontinue with step 706.

In step 706, MR 124 can route the message to an appropriate PG 116 asdiscussed above with reference to FIG. 1C.

In step 708, the simple network transport layer (SNTL) applicationrunning on the PG 116 can segment the message into multiple segments,can encapsulate the segments with an SNTL segment header 900, and cantransmit the segments of the message to the client device 112. Anexemplary embodiment of a message header 900 is illustrated below withreference to FIG. 9. As will be apparent to those skilled in therelevant art, due to a high bit error rate in wireless communicationlinks, it can be expected that potentially not all transmissions from PG116 will be received at the client device 112. From step 708, the flowdiagram can continue with step 710.

In step 710, client device 112 can send to the PG 116 an acknowledgement(ACK) of receipt of the transmitted messages at the client device 112.As shown, in the exemplary embodiment, receipt of only segment 1 isacknowledged. Receipt of segment 2 is not acknowledged. From step 710,the flow diagram 702 can continue with step 712.

In step 712, in an exemplary embodiment, PG 116 can automatically retry,or retransmit segment 2 of the message to the client device 112, sinceacknowledgement of receipt was not received for segment 2 in step 710.From step 712, flow diagram 702 can continue with step 714.

In step 714, client device 112 can transmit the complete multi-segmentmessage to PG 116. From step 714, flow diagram 702 can continue withstep 716.

In step 716, PG 716 can send an acknowledgement of receipt of themulti-segment message to MR 124. From step 716, flow diagram 702 cancontinue with step 718.

In step 718, MR 124 can send acknowledgement of receipt of themulti-segment message at the client 112 on to the BES 122. From step718, flow diagram 702 can immediately end.

The flow diagram 702 can be used in one exemplary embodiment to send aresponse from BES 122 to a request originating from client 112. Inanother exemplary embodiment, flow diagram 702 can be used to generatean unsolicited response, also commonly referred to as an “alert,” or a“push.” It is important to note that acknowledgement of receipt of aresponse message, as shown for example in flow diagram 702, is optional.For example, in the case of some client devices 112, such as, e.g., withsome paging devices, it may be impossible to send back from the clientdevices 112 an acknowledgment.

FIG. 8A illustrates a flow diagram 800 depicting an exemplary embodimentof the present invention. Flow diagram 800 numerically depicts a flow ofmessages that corresponds to an alert that can be sent from a BES 122 toa client application at client device 112. Flow diagram 800, in anexemplary embodiment, can proceed similarly to the method detailed inflow diagram 700 above describing sending a response message to arequest. A BES 122 unsolicited alert can be sent to client applicationand can differ only slightly from the response from BES 122 to a clientapplication flow. The difference can include that the response messageto a request is given the client device 112 object information when theBES 122 receives the request and can use this object to send theresponse. In an exemplary embodiment, the object information can includea hidden linkstation id. When a BES 122 sends an alert, the BES 122 isresponsible for constructing the client device 112 object informationwith the proper Customer ID and Device ID. The linkstation id that ishidden may be null. However the BES 122 can know the customer ID or thecustomer ID and the port number of the client application running onclient device 112. The BES 122 can know only about the customer id anddevice id. The device id can be set to the defined ALL_DEVICES value. Inone embodiment, the port number of the client application is not needed.By setting the customer id and device id, the BES 122 can target aspecific client device 112. If the device id is set to ALL_DEVICES, thenthe message should be sent to all of the customer's devices 112. Flowdiagram 800 of FIG. 8 numerically shows an exemplary alert message flowfrom the BES 122 through MR 124, and PG 116 to the client applicationrunning on the client device 112 including several exemplary stepslabeled by numbers 1-5, as follows:

-   1. A BES 122 can send an unsolicited alert to a client application.    The BES can pass the client device 112 information object, the alert    message, the message send flags, (ACK_REQUIRED, SEND_IF_ACTIVE_ONLY,    SEND_ONLY_ONCE), compression flag, and encryption flag on the send    call.

The customer/application information can include the customer ID or thecustomer ID and the port number of the client application running onclient device 112. Message flags can specify whether to compress and/orencrypt the message and whether the BES 122 requires an ACK message whenthe PG 116 has successfully delivered the message to the clientapplication. The BES 122 can then send the alert message to the nextavailable MR 124. If no MRs 124 are available, then a false can bereturned from the send call. The client device 112 information objectcan include the customer id and device id. Device id can be set todefine the value of ALL_DEVICES if the BES 122 wants to send the alertto all devices 112 owned by the customer. Or the BES 122 can specify aspecific device id if the BES 122 wants to target a specific customer'sdevice 112. Message flags can specify 1) whether the BES 122 requires anACK message when the PG 116 has successfully delivered the message tothe client application (ACK_REQUIRED), 2) that the intelligent messagingnetwork only try sending the alert if the client is active on theintelligent messaging network (SEND_IF_ACTIVE_ONLY), 3) that the PG 116should only try sending the message once and not perform retries(SEND_ONLY_ONCE). The compression flags can indicate if the messageneeds to be compressed or not and if so what algorithm to use. Theencryption flags can indicate if the message needs to be encrypted ornot and if so what encryption algorithm to use.

-   2. The MR 124 can use the customer/application information to send    the alert message. In particular, the MR 124 can use the customer id    and device id information to send the alert message.

If the customer/application information includes only the customer ID,then the MR 124 can search the local cache of the MR 124 and can searchthe ActiveUsers table to obtain the LinkStationID associated with thecustomer ID. If the customer/application includes both the customer IDand application port number then the MR 124 can search the local cacheof the MR 124 and can search the first device assigned to the customerID in the AuthorizedDevices table to obtain the LinkStationID. The MR124 can use the LinkStationID to determine the associated communicationtype (e.g., CDPD, Mobitex, etc.) and can send the message to the nextavailable PG 116 of the correct communication type. If thecustomer/application information includes only the customer ID and theLinkStationID and these are not found in the local cache or ActiveUserstable, the MR 124 cannot send the outgoing message to the clientapplication, in an exemplary embodiment. Therefore the MR 124 can send acustomer inactive message back to the BES 122 that was the source of theoutgoing message. If the customer/application information is both thecustomer ID and port number of the client application running on clientdevice 112, then the message can always be sent if a device address isfound in the AuthorizedDevices table for the customer ID. In anexemplary embodiment, the linkstation id in the client deviceinformation is null so the MR 124 will use the customer id and device idto construct one or more linkstation id(s). The following are 4exemplary scenarios. 1) If the message send flag is set toSEND_IF_ACTIVE_ONLY and device id is specified, then the MR 124 canfirst look in its local cache to obtain the linkstation id of thespecified device. If the device, is not found in its local cache, thenthe MR 124 can look in the ActiveUsers table to obtain the linkstationid of the customer's device 112, (the device 112 could be active withinthe intelligent messaging network on some other MR 124) 2) If themessage send flag is set to SEND_IF_ACTIVE_ONLY and device id is set toALL_DEVICES, then the MR 124 can look in the ActiveUsers table to obtainthe linkstation id's of all the customer's devices 112 active on thenetwork. 3) If the message flag is not set to SEND_IF_ACTIVE_ONLY andthe device id is specified, then the MR 124 can first look in its localcache to obtain the linkstation id of the specified device 112. If thedevice 112 is not found in, its local cache, then the MR 124 can look inthe AuthorizedDevices table to obtain the linkstation id. 4) If themessage flag is not set to SEND_IF_ACTIVE_ONLY and the device id is setto ALL_DEVICES, then all of the customer's device(s) 112 informationshould be retrieved from the AuthorizedDevices table. Using theretrieved information, the MR 124 can construct the linkstation id(s).If the device(s) are found, either from the cache or database, the MR124 can use the Linkstation id of each device to determine theassociated communication type (e.g., CDPD, Mobitex) and can send themessage for each linkstation id(s) to the next available PG 116 of thecorrect type. If no device(s) are found, the MR 124 can send a customerinactive message if the send message flag is set to SEND_IF_ACTIVE_ONLYotherwise the MR can send a customer not valid message back to the BES122 that was the source of the alert message.

-   -   If ALL_DEVICES is set for the device id, then once the MR 124        has found all the devices for a particular customer, the MR 124        can send back to the BES 122 each of the device id's found (to        correlate the ACK's) before it sends the alert message to the PG        116. The reader is directed to FIG. 8B depicts an exemplary        hybrid alert for sending to one or more devices and FIG. 8C        depicts an example of negative acknowledgments of an alert and a        response providing client device 112 availability back to the        BES 122.

-   3. The PG 116 can segment the alert (if necessary) and can transmit    the alert over the network (see FIG. 6B for more information    regarding multiple segment responses or alerts);

-   4. The transport protocol layer can receive the message segment and    can assemble the message segment into a complete alert (if    necessary); the transport protocol layer can send a transport ACK    message to the PG 116 that sent the message; it is important to note    that, in some exemplary embodiments, sending ACK messages can be    optional. Once the transport assembles the message, it can send the    message to any applications that are running the transport protocol    layer and that have expressed interest in the same type of message    as the alert message. Once the message is delivered to the    application, the transport can then send the transport ACK to the PG    116 that sent the message. In one embodiment, the transport ACK is    preferably sent back to the PG 116, however this can also be    optional.

-   5. The PG 116 can receive the transport ACK from the client    application running on client device 112, and can send an ACK    control message back to the BES 122 that was the source of the    original message (if required).

FIG. 8B depicts an exemplary embodiment of a flow diagram 802illustrating transmission of a hybrid alert from BES 122 to clientdevices 112 a, 112 b. Flow diagram 802 can begin with step 804.

In step 804, BES 122 can send a hybrid alert message to MR 124 for aclient user who can have multiple client devices 112 a, 112 b. In anexemplary embodiment, the hybrid alert can include XML query conditions.The query can query, e.g., the MR. DB 128 to determine the status ofparticular conditions. For example, the client user could have multipledevices and the client user's client record can indicate that redundantalerts should be sent to all devices at once. Alternatively, the clientuser's client record could indicate, e.g., that a message should be sentto a primary, or highest priority device first, and if the BES 122receives no acknowledgement of receipt of the message from the primarydevice, then a message can be sent to a secondary or lower prioritydevice, and so on, in the event that the client user has multiple clientdevices. From step 804, flow diagram 802 can continue with step 806 a or806 b.

In an exemplary embodiment, the MR 124 can route the hybrid alertmessage to any of client devices 112 that match the query conditions. Inone exemplary embodiment, the hybrid alert message can be sent to alldevices 112 a, 112 b. Suppose the criterion are such that the hybridalert is to be sent to both client devices 112 a and 112 b. The hybridalerts can be sent in parallel or sequentially.

In step 806 a, MR 124 can route the hybrid message to PG 116 a. Fromstep 806 a, flow diagram 802 can continue with step 808 a.

In step 806 b, MR 124 can route the hybrid message to PG 116 b. Fromstep 806 b, flow diagram 802 can continue with step 808 b.

In step 808 a, PG 116 a can route the hybrid alert message to clientdevice 112 a. From step 808 a, flow diagram 802 can continue with step810 a.

In step 808 b, PG 116 b can route the hybrid alert message to clientdevice 112 b. From step 808 b, flow diagram 802 can continue with step810 b.

In step 810 a, in one embodiment, client device 112 a can send back toPG 116 a a message acknowledging receipt of the hybrid alert message.Acknowledgment of receipt of an alert can be optional. From step 810 a,flow diagram 802 can continue with step 812 a.

In step 810 b, in one embodiment, client device 112 b can send back toPG 116 b a message acknowledging receipt of the hybrid alert message.Acknowledgment of receipt of an alert can be optional. From step 810 b,flow diagram 802 can continue with step 812 b.

In step 812 a, in an exemplary embodiment, the PG 116 a can forward onthe acknowledgement of receipt at the client device 112 a to MR 124.From step 812 a, flow diagram 802 can continue with step 814 a.

In step 812 b, in an exemplary embodiment, the PG 116 b can forward onthe acknowledgement of receipt at the client device 112 b to MR 124.From step 812 b, flow diagram 802 can continue with step 814 b.

In step 814 a, in an exemplary embodiment, MR 124 can forward theacknowledgment of receipt on to BES 122.

In step 814 b, in an exemplary embodiment, MR 124 can forward theacknowledgment of receipt on to BES 122.

FIG. 8C depicts an exemplary embodiment of a flow diagram 816illustrating a client device 112 a which becomes unavailable whentransmissions are being sent to it, which can prompt a hybrid alert tobe sent to another client device 112 b as shown, e.g., in flow diagram802 of FIG. 8B. Flow diagram 816 can begin with step 818.

In step 818, BES 122 can attempt to send an alert to MR 124 intended forclient device 112 a. From step 818, flow diagram 816 can continue withstep 820.

In step 820; MR 124 can route the alert to a PG 116 a associated withclient device 112 a. From step 820, flow diagram 816 can continue withstep 822.

In step 822, according to the exemplary embodiment, suppose clientdevice 112 a is unavailable to receive, and thus a negativeacknowledgement of receipt (NACK) can be sent to MR 124. In oneembodiment, the PG 116 a can be aware that an alternate path can beavailable, i.e., that another client device 112 b with which the BES 122can communicate. From step 822, flow diagram 816 can continue with step824.

In step 824, the negative acknowledgement (NACK) of receipt at clientdevice 112 a can be forwarded on from the MR 124 to BES 122. BES 122 canbe notified in the NACK, in one embodiment, that the BES 122 can sendthe alert using a hybrid alert such as, e.g., that depicted in flowdiagram 802 of FIG. 8B, to reach the client user using client device 112b (not shown in FIG. 5C).

Flow diagram 816 also depicts a request from client device 112 a beingsent to BES 122 which can begin with step 826.

In step 826, the client device 112 a can send a request message to a PG116 a. From step 826, flow diagram 816 can continue with step 828.

In step 828, PG 116 a can forward the request on to MR 124. From step828, flow diagram 816 can continue with step 830.

In step 830, MR 124 can forward the request to BES 122. From step 830,flow diagram 816 can continue with step 832.

In step 832, BES 122 can send a response message intended for clientdevice 112 a to MR 124. From step 832, flow diagram 816 can continuewith step 834.

In step 834, MR 124 can route the response message to a PG 116 aassociated with intended recipient, client device 112 a. From step 834,flow diagram 816 can continue with step 836.

In step 836, suppose that the PG 116 a determines that client device 112a is unavailable to receive a message, so a negative acknowledgment ofreceipt of the response message at the client device 112 a can be sentto MR 124. From step 836, flow diagram 816 can continue with step 838.

In step 838, MR 124 can forward on the NACK message to BES 122 notifyingBES 122 that the response message was not received by client device 112a. In an exemplary embodiment, BES 122 can be notified that the clientuser can be reached using another client device 112 b. BES 122 can benotified in the NACK, that the BES 122 can send the response messageding a hybrid alert such as, e.g., that depicted in flow diagram 802 ofFIG. 8B, to reach the client user using client device 112 b (not shownin FIG. 8C).VII. Software Development Kits

A. Mobile Client SDK

The Mobile client SDK is comprised of the following set of platformspecific libraries. Each of the following exemplary libraries exports aneasy to use API:

-   -   Utility Library;    -   Transport Library; and    -   Security Library.

An exemplary embodiment of the invention, includes a utility libraryproviding compression services. By keeping the transport libraryindependent from both the utility and security implementation details,new compression and security mechanisms can be added without theknowledge of the transport library. The independence eliminates the needto regression test the transport library, as well as all applicationusers of the transport library when adding a new compression or securitymechanism. Because the compression and security solutions may not meetthe need for all intelligent messaging network enabled applications,when new applications are developed, any specific compression orsecurity requirements of such applications may be accommodatedtransparent to the transport library individually, on a component basis.By providing wrapper APIs that encapsulate the default implementation ofthe utility and/or security libraries, developers could choose to writeto the wrapper APIs, or directly to the utility and/or security APIs.

1. Utility Library of the Intelligent Messaging Network

The utility library of the intelligent messaging network can provideapplications with functions to perform via an easy to use API. Thefollowing section summarizes the major functions provided by the utilitylibrary.

A. I/O Streaming

Provides functions to assist developers with handling applicationmessages that are streaming in and out (two ways). Serial in and outfunctions are provided for most of the common data types supported bythe target platform. The streaming functions manage the big-endianlittle-endian issues on behalf of the application.

B. Compression Mechanism

Applications can optionally compress/encode application messages priorto transmitting the message to a target destination. If the encodealgorithm determines that it is not optimal to encode the message, themessage is not encoded. Also, applications can optionally decodeapplication messages prior to processing the message. In order todetermine if a message needs to be decoded, applications can check theencode flag contained in the message header.

C. AIM Message Header

Every application message is pre-fixed with the intelligent messagingnetwork message header prior to being sent to its target destination.The intelligent messaging network utility library provides applicationswith functions to set/get the contents of the intelligent messagingnetwork message header. It also provides functions to serial out andserial in the contents of the intelligent messaging network messageheader. Applications are not required to know the internal datarepresentation of the intelligent messaging network message header.

D. AIM Authentication Messages

In order to access the intelligent messaging network via an ISP dialupconnection, the intelligent messaging network requires that the userprovide security credentials to identify themselves. The intelligentmessaging network utility library provides functions to build theintelligent messaging network authentication request message.Applications are not required to know the internal data representationof the intelligent messaging network authentication request message,likewise for the intelligent messaging network authentication responsemessage. Functions are provided to determine the authentication statusof the request.

2. Transport Library of the Intelligent Messaging Network

The transport library provides reliable, optimized data communicationover various wireless networks, such as the CDPD and Mobitex wirelessnetworks, as well as ISP dialup wire line access to enabled theintelligent messaging network client applications via an easy to useAPI. The following section summarizes the major functions provided bythe mobile client transport library.

-   -   Designate Target Destination—The client application can specify        the target destination of the machine to receive the message.    -   Notification of Success/Failure of Transmission—The client        application receives notification of the success or failure of        the message transmission. For those platforms that support a        multi-threaded environment (e.g. WinCE), the notification        mechanism is via an event that the transport library asserts.        For those platforms that do not support a multi-threaded        environment (e.g. Palm OS), the client application is required        to continuously poll the transport library to determine if the        message transmission was successful or failed.    -   Message Segmentation—All messages that are greater than the        maximum segment size (configurable) are segmented into multiple        message segments.    -   Message Re-Assembly—All multi-segmented messages received are        re-assembled into a single message prior to presenting the        message to the client application running on client device 112.    -   Message Retries—All message segments that are not acknowledged        by the peer wireless protocol layer within the configured time        are retried the configured number of attempts before notifying        the client application that the message was delivered        (acknowledgment) or not (negative acknowledgment).    -   Configurable Communication Parameters—The communication        parameters for the mobile client transport library can be        tailored to the required communication behavior. These values        can be configured via the registry (WinX platforms) or the        preferences database (Palm OS platforms) prior to opening the        mobile client transport library.    -   Duplicate Message Segment Detection—All duplicate message        segments received by the mobile client transport library are        acknowledged back to the peer wireless protocol layer,        discarded, and conditionally logged.    -   Duplicate Message Detection—All duplicate messages received by        the mobile client transport library are acknowledged back to the        peer wireless protocol layer, discarded, and conditionally        logged.

A layered architecture can be used for developing the transport library.Under this arrangement, each layer (excluding the bottom) can encompasscertain functions, can request services from the layer directly belowit, and each layer (excluding the top) can provide services to the layerdirectly above it. In order for a layer to do the job it is assigned toperform; layer N employs the services of layer N−1. The division of thenetwork into logical layers can allow a higher level to make use of themore primitive functions of lower levels, without having the layerconcern itself with the implementation details of those primitives.

A. Protocol Stack

FIG. 3 depicts an exemplary embodiment of a block diagram 300 of thepresent invention. Block diagram 300 illustrates a proprietary wirelessprotocol stack of the present invention including a mapping to thelayers of the OSI model as illustrated in the left column. Like theTCP/IP protocol stack, the protocol stack of the present inventionincludes only 5 layers. The highest layer is the applications layer,which corresponds to layer 7 in the OSI protocol stack reference model.Layer 4, the transport layer is the proprietary simple network transport(SNTL) layer of the present invention. Layer 3 is the network layer,corresponding to OSI layer 3. Layers one and two of the OSI model havebeen combined in the figure for ease of reference and include the datalink and physical layers for a variety of supported protocols forspecific classes of client devices. Because symmetry is assumed, each ofthe PGs 116 has a symmetrical protocol stack. Each client device 112 canhave only one of the combination layers corresponding to OSI layers oneand two. Similarly, while each of the PGs 116 could have one or more ofthe layers corresponding to the combination OSI layer one and two, anexemplary embodiment can include for each PG 116 having only onecombination layer corresponding to layer one and two.

i. Application Layer

The function of application layer (layer 7 of the OSI stack) is toprovide an interface between the application and the transport protocollayer by which client applications can send and receive messages acrossmultiple wireless networks (or via dial-up ISP access) without havingknowledge of the communication implementation.

In an exemplary embodiment of the present invention, layers 4 caninclude, e.g., applications such as, e.g., mail, file transfer, andother applications such as, e.g., end user applications.

ii. Transport Layer

This layer logically represents layer 4 of the reference model for thepresent invention. This layer provides the control structure formanaging the communications between two communicating peer transportlayers. The following sections detail the functions provided by thisprotocol layer.

The highest layer is the application layer. Layer 4 is the transportlayer and, in an exemplary embodiment, includes a connectionlessUDP-like transport protocol that has many of the features and advantagesof TCP. That is, the transport layer is connectionless like UDP but hasmany of the features of TCP including but not limited to messagesegmentation, message segment reassembly, message retries, and messageduplication but has only a four to six byte header.

In an exemplary embodiment of the present invention, layers 4 caninclude, e.g., the simple network transport layer (SNTL) protocol of thepresent invention.

iii. Lower Layers

The network layer (layer 3) such as, e.g., the Internet Protocol (IP)layer is responsible for providing network protocol layer functionalityand hiding the details of this functionality from the transport layer.Below the network protocol layer is the data link protocol layer (layer2) and finally the physical protocol layer, which handles modulation andradio transmission.

In an exemplary embodiment of the present invention, layers 1 and 2 caninclude any of, e.g., the PSTN 308 a, CDPD 308 b, Mobitex 308 c, Ardis308 d, CPRS, and other, and future protocols 308 e, and GSM 308 f.

Message Segmentation

All messages to be sent over the network that exceed the maximum segmentsize (configurable) are segmented into multiple message segments. Thesegment size is configured prior to the client application opening thetransport library. The default maximum segment size is 512 bytes.

Segment Header

A transport header is prefixed to every outbound message segment. Thetransport header is encoded in network-byte order. It is the soleresponsibility of the application to encode any application specificdata in network-byte order prior to calling the AeTransportSendinterface function. The diagram below details the transport headerfields.

FIG. 9 illustrates a diagram 900 illustrating an exemplary embodiment ofthe present invention. Diagram 900 depicts an exemplary embodiment of anexemplary segment header and exemplary components 902-910 of the header.In an example embodiment, a type I header can include a single segmentmessage header, and a type II header can include a multiple segmentmessage header. It will be apparent to those skilled in the relevantart, that various other header formats can be used within the spirit andscope of the present invention.

-   -   VER 902        -   This field contains the version number of the Segment            Header. It consists of two bits, bit 0 and bit 1 of the            1^(st) word in the Segment Header. Valid values are 0            through 3.    -   MESSAGE ID 904        -   This field contains a message identification value. It            consists of thirteen bits, bits 2 through 14 of the 1^(st)            word in the segment header. Valid values are 0 through            8,192. The transport protocol layer uses the message ID to            discard segment/message duplications and to match            acknowledgments with messages.    -   FLAGS 906        -   This field contains protocol information. It consists of            five bits, bits 15 through 19. Valid values are:        -   Bit 19—segmentation indicator (0—message not segmented,            1—message segmented)        -   Bit 18—reserved        -   Bit 17—reserved        -   Bit 16—message type (0—positive acknowledgment,        -   1—negative acknowledgment)        -   Bit 15—message indicator (0—application message,    -   1—AIM control message)    -   TOTAL LENGTH 908        -   This field contains the total number of bytes contained in            the message segment to be sent including the segment header.            It consists of twelve bits, bits 20 through 31 of the 2^(nd)            word in the segment header. Valid values are 4 through            4,096.    -   SEGMENT NUMBER 910        -   This field identifies the number of this message segment. It            consists of 8 bits, bits 0 through 7 of the 3^(rd) word in            the segment header. Valid values are 2 through 255. The peer            wireless protocol layer uses this number to re-order the            message segments into a single complete message. NOTE: This            field is present only if the segmentation indicator is set            in the flags field.

Notification of Success/Failure of Transmission

The transport protocol layer retains knowledge of all outstandingmessage segments pending acknowledgment (message segments that have notbeen acknowledged by the peer wireless protocol layer) via a pendingacknowledgment queue. The pending acknowledgment queue maintainsinformation pertaining to message segments that have been successfullytransmitted and are pending acknowledgment from the peer wirelessprotocol layer. If an acknowledgment (positive or negative) is receivedfor a message segment that is not pending acknowledgment, the ACK isdiscarded and conditionally logged.

When all message segments have been positively acknowledged by the peerwireless protocol layer, the application is notified (if requested) witha message type of AIM ACK MESSAGE and the message ID value associatedwith the sent message. If the number of transmission attempts for themessage segment has exceeded the configured number of retry attempts,the application is notified with a message type of AIM_NACK_MESSAGE, themessage ID value associated with the sent message, and the 2 byte errorcode containing the reason why the message was not delivered. In orderto re-send a message that has been negatively acknowledged, theapplication calls a AeTransportSend interface function.

Message Retries

All message segments not acknowledged by the peer wireless protocollayer within the configured time are automatically re-transmitted. Thetime to wait for an acknowledgment from the peer wireless protocol layeris configured prior to the client application opening the transportlibrary. The default time to wait for an acknowledgment from the peerwireless protocol layer can for example be 15 seconds.

The transport protocol layer retries the configured number of timesbefore notifying the application that the message could not be delivered(negative acknowledgment). The number of times to retry is configuredprior to the client application opening the transport library. Thedefault number of retry attempts is 3.

Message Re-Assembly

All incoming message segments received (including duplicate segments)are immediately acknowledged back to the peer wireless protocol layerand are queued pending receipt of all message segments via the inboundmessage queues. The incoming message queues manages a separate inboundmessage queue for each different LinkStationID of the sender.

When all message segments have been received for a message, the segmentsare assembled into a complete message. If the message ID of theassembled message has been already received (duplicate message), themessage is discarded and conditionally logged. This layer keeps track ofthe last n message IDs received for each unique LinkStationID. Thenumber of message IDs to contain in the message look back queue isconfigured prior to the client application calling AeTransportOpen toopen the transport library. The default number of message IDs tomaintain in the message look back queue may be set to 10, for example.

The exemplary message header 900 of FIG. 9 includes segment number field910 which can be used to identify the segment number of a multi-segmentmessage. For multiple segment messages, an additional field (not shown)can be used to identify the total number of segments in a message. In anexemplary embodiment, the total number of segments field could be 2bytes wide. Advantageously, according to an exemplary embodiment of thepresent invention, the simple network transport layer (SNTL) can use theinformation in the total number of segments field to determine whichsegments of the total number sent were received as acknowledged, or arerequired to be retransmitted. The reader is directed to FIGS. 6B and 7Babove illustrating transmitting a multi-segment message, and retryingwhere a segment is not acknowledged.

3. Security Library of the Intelligent Messaging Network

The security library provides encryption and decryption services to theintelligent messaging network enabled applications via an easy to useAPI. The initial security mechanism is based on Certicon'simplementation. The following section summarizes the major functionsprovided by the security library.

-   -   Key Exchange—Public and private keys are used periodically to        establish a common secret key that both the client application        running on a client device and server use when exchanging        messages. The reason for this is that the overhead of encrypting        using public/private keys is much higher than when using a        single secret key. The message flows to securely establish a        secret key between a client application running on a client        device and a server is the responsibility of the security        library.    -   Encryption—Mobile client application running on a client device        can optionally encrypt application messages prior to        transmitting the message to the target destination. Messages are        encrypted with the secret key negotiated between the client        application running on a client device and the server.        Encryption is always performed after compression.    -   Decryption—Mobile client applications running on a client device        can optionally decrypt client application messages prior to        processing the message. To determine if a message needs to be        decrypted, client applications can check the encryption flag        contained in the message header. Messages are decrypted with the        secret key negotiated between the client applications running on        a client device and the server. Decryption is always performed        before compression.

B. Server Software Development Kit (SDK)

The Intelligent messaging network provides a server SDK environment toassist engineers developing PGs 116 and BESs 122. The server SDK iscomprised of an easy to use C++ API and a set of Windows NT 4.0libraries. The SDK can be logically divided into the following twocategories of classes:

-   -   1. Server classes—These are the core classes that server        application developers use when creating new PGs 116 and BESs        122. These classes have no Graphical User Interface (GUI);        thereby allowing developers to provide their own custom        interfaces.    -   2. Server user interface classes—These classes provide a        graphical interface to the Server classes. Use of these classes        is not required when developing a new Server.        AIM Server Classes

The Server classes are organized in the following simple classhierarchy:

AeServer Class

The AeServer class is the base class for all of the other Server classesand encapsulates those functions that are common to all Servers. Theseinclude:

Server Registration/Deregistration—Server subclassesregister/de-register from the intelligent messaging network MR database128 themselves, using methods defined in this class.

Server to Server Connectivity—The logic that determines how two Serverslocate and connect to one another is implemented in the AeServer class.The connection flow consists of both establishing a TCP/IP connection aswell as the mutual exchange of ServerConnect messages as a means ofverifying the identify of each server.Server to Server Communication (TCP/IP)—AeServer encapsulates the TCP/IPcommunication between all Servers. Servers can use the communicationfunctions provided by this class to connect, disconnect, send messages,and receive messages over a TCP/IP connection to other Servers. TheAIMSvrPacket is the standard unit of communication between all Servers.The sequence of fields that comprise the AIMSvrPacket is as follows:

AIMSvrPacket Layout

-   -   Version (4 bits)—The version number of the AIMSvrPacket.    -   Header Length (4 bits)—The length of the AIMSvrPacket header in        bytes. The AIMSvrPacket header consists of the first 5 fields of        the AIMSvrPacket: version, header length, flags, total packet        length and source server ID. This length is used by the TCP        connection classes to read enough of the packet in order to        determine the total size of the remainder of the packet.    -   Flags (BYTE)—contains protocol information. It consists of eight        flag bits, valid values are:    -   Bit 1—acknowledgment indicator (1—ACK required, 0—ACK not        required).    -   Bit 2—message type indicator (1—server connect message)    -   Bits 3-8—reserved for future use.    -   Total Packet Length (unsigned long)—Contains the total number of        bytes in the AIMSvrPacket (including the packet header).    -   Source Server Database ID (unsigned long)—Contains Database ID        (a unique value assigned to an Server when the Server registers        itself in the intelligent messaging network MR database 128 of        the originator of the packet.    -   LinkStationID (variable length)—Contains the device address of        the source or destination of the message contained in the        packet. This field's size and content varies depending on the        communications type (CDPD, Mobitex, etc) of the device.    -   Message ID (unsigned short)—server packet message identifier.    -   Customer ID (unsigned long)—intelligent messaging network MR        database 128 ID of the customer who owns the device targeted by        the message in the server packet. Although always present, this        field does not always contain a valid value and is set to 0 when        not valid. This field is not valid when the AIMSvrPacket        contains a network control message (server-to-server messages        independent of application messages) or when passing a client        message to/from a PG 116 and MR 124. The primary purpose of the        field is for MR 124 to BES 122 communications; to identify the        message source on incoming messages, and target a specific        customer device on outgoing messages.    -   Port Number (unsigned short)—customer device port number.        Although always present in the packet, this field only contains        a valid (non-zero) value when a BES 122 sends an unsolicited        message to a device.    -   Intelligent Messaging Network Message Header (in an exemplary        embodiment can include 6 BYTES)—All application messages prefix        the intelligent messaging network message header to the        beginning of the application message. The intelligent messaging        network message header consists of the following fields:    -   1. Compression Bits (3-bits)—0=message is not compressed, 1=AIM        supplied compression type, 2=Aether supplied compression type,        3=application supplied compression type.    -   2. Security Bits (3-bits)—0=message is not encrypted, 1=AIM        supplied encryption, 2=Aether supplied encryption, 3=application        supplied encryption.    -   3. Version (3-bits)−Message header version.    -   4. Reserved Bits (7-bits)—Reserved for future versions.    -   5. Service Type (12-bits)—Identifies which type of service        (MarketClip, FX) the message pertains to. This field is used by        both indirect and direct routing.    -   6. Message Type (12-bits)—Uniquely identifies the message within        the context of the specified service type.    -   7. Server ID (1-byte)—Identifies a specific BES 122 of the given        service type. The value of 0 is reserved to indicate that        indirect muting is desired. A non-zero value indicates that the        message is targeted at a specific BES 122.    -   Message Body (variable length)—Contains the body of the        application message.        AeFEServer Class (for the PGs)

The AeFEServer class subclasses AeServer and encapsulates thosefunctions that are common to all PGs 116. All PGs 116 derived from theAeFEServer class. This class performs the following functions on behalfof all PGs 116:

-   -   Encapsulates the Transport Header—Only this class knows the        implementation details of the transport header. The transport        header contains control information for communicating between        the intelligent messaging network enabled client applications        and PGs 116.    -   Asynchronous (non-blocking) Notification of Success/Failure of        Transmission—This class optionally notifies the original sender        of the message indication of the success or failure of the        message transmitted to the client application running on client        device 112.    -   Message Segmentation—All outbound server messages to be sent to        the client application that are greater than the maximum segment        size (configurable) is segmented into multiple message segments.    -   Message Re-Assembly—All multi-segmented messages received from        the client application are re-assembled into a single message        prior to sending the message to a MR 124 to route to a        registered BES 122.    -   Message Retries—All message segments that are not acknowledged        by the client device peer wireless protocol layer within the        configured time is retried the configured number of attempts        before notifying the original sender that the message was        delivered (acknowledgment) or not (negative acknowledgment).    -   Message Pacing—For large multi-segmented messages, many device        modems cannot keep up if they are quickly flooded with a series        of segments. PGs 116 contain a configurable setting that can be        set to slow up the transmission of messages larger than a        specified number of segments.    -   Duplicate Message Segment Detection—All duplicate message        segments received from the client device are acknowledged back        to the client device peer wireless protocol layer, discarded,        and conditionally logged.    -   Duplicate Message Detection—All duplicate messages received from        the client device is acknowledged back to the client device peer        wireless protocol layer, discarded, and conditionally logged.    -   Configurable Communication Preferences—The communication        parameters for the PG 116 can be configured to tailor the        communication behavior. These values are configured prior to the        starting the PG 116.        AeBEServer Class

The AeBEServer class subclasses from AeServer and encapsulates thosefunctions that are common to all BESs 122. This class performs thefollowing functions on behalf of all BESs 122:

-   -   Generate ACK Control Messages—When this class receives an        incoming from a PG 116 routed via MR 124, it creates an ACK        control message and send it back to the originating PG 116 via a        MR 124. When the PG 116 receives this ACK control message, it        sends a transport layer ACK message to the client application on        a client device that originated the message indicating that the        message was delivered to the BES 122.    -   Process ACK Control Messages—When this class receives an ACK        control message from a PG 116, indicating that the server        application message was delivered to the client device, it        notifies the derived BES 122.    -   Message Compression/Decompression—AeBEServer is responsible for        compressing any outgoing messages and decompressing incoming        messages. If an AIM provided compression type is involved,        compression/decompression is done transparently relative to any        subclasses of this type. Alternately, AeBEServer subclasses may        implement compression in their message serialization.    -   Message Encryption/Decryption—AeBEServer is responsible for        encrypting any outgoing messages and decrypting incoming        messages. If an AIM provided encryption type is involved,        encryption/decryption is done transparently relative to any        subclasses of this type. Alternately, AeBEServer subclasses may        implement their own encryption algorithms by implementing the        appropriate virtual methods that is invoked by AeBEServer at the        appropriate times.        Derived PGs 116

All the intelligent messaging network developed PGs 116 are derived fromthe AeFEServer class. Derived PGs 116 provide the following functions:

-   -   Encapsulate the Communication Layer—Derived PGs 116 provide the        network specific interface to the communication layer used by        the PG 116. The parent class (AeFEServer) does not know the        implementation details of the underlying protocol layer used to        send and receive messages to and from client applications        running on client devices 112. This is the sole responsibility        of the derived PG 116.        Derived BESs 122

All BESs 122, developed by the intelligent messaging network can bederived from either the AeBEServer. Derived BESs 122 provide thefollowing functions:

-   -   Process application Specific Messages—All application specific        knowledge is implemented in the derived BES 122. For example, a        news service can provide client devices with news stories        related to a specific financial entity. The derived news        server's parent class hierarchy (AeBEServer and AeServer) does        not know the implementation details of the application message        protocol. This is the sole responsibility of the derived BES        122.    -   Special Compression Services—If a BES 122 has specific        compression requirements for their application data that is not        addressed by the Intelligent messaging network supplied        compression, the BES 122 is responsible for providing the        compression mechanism.    -   Special Security Services—If a BES 122 has specific encryption        requirements for their application data that is not addressed by        the Intelligent messaging network supplied encryption, the        derived BES 122 is responsible for providing the encryption        mechanism.        Server User Interface Classes

The server user interface class hierarchy parallels the Server classhierarchy and provides the following types of functionality:

-   1. Persistent storage of configurable server settings as well as a    common user interface for viewing/editing those settings.-   2. Screen based error logging.-   3. NT Event Log error logging and automatic batch file error    notification.-   4. Inbound/outbound message logging.-   5. Inbound/outbound message statistics.    AeServerApp

AeServerApp is the base class for all of the other Server GUI apps. AllServer applications are complete, windows-based, executable programs.AeServerApp expects its subclasses to provide it with an instance of anAeServer subclass. Of the five areas of functionality listed above,AeServerApp provides the following:

-   1. Persistent storage of configurable server settings and common    user interface framework for viewing/editing those settings.    —Persistent storage is implement through the Windows registry and    AeServerApp provides the base registry key for all of its subclasses    to use. AeServerApp also provides a standard method of    viewing/editing server settings in the form of a PropertySheet.    Subclasses provide for their own individual server settings by    adding PropertyPages to the base class PropertySheet. AeServerApp    provides a common page for handling server settings common to all    server types.-   2. Screen based error logging. —In addition to providing a window    where system events and errors can be displayed, AeServerApp also    supplies a separate logging thread that can be used by subclasses    when displaying output to their own windows. This thread runs at    lower priority then the server processing threads so that screen    logging does not negatively impact performance.-   3. NT Event Log error logging and automatic batch file error    notification. —AeServerApp provides a mechanism whereby system    errors can be written to the NT Event log. The level of error    reporting is configurable. In addition to the NT Event log, users    may specify that a batch file be executed when an error of a    specified severity occurs. Such batch files could be used to    communicate problems to a system administrator via email or a pager.    AeFEServerApp

AeFEServerApp is derived from AeServerApp and provides the followingadditional user interface features:

-   1. PG specific server settings—Provides a user interface and    persistent storage for transport settings such as maximum number of    retries, retry timeout interval, segment size, etc.-   2. Inbound/Outbound message logging—Provides two windows that log    each inbound and outbound message. Makes use of the AeServerApp    logging thread. Logging may be enabled/disabled for either window.-   3. PG specific statistics—Gathers and displays statistical totals    such as number of messages sent/received, number of ACKS/NACKS    sent/received.    AeBEServerApp and CBEServerSampleApp

These classes provide a standard GUI for BESs 122. Both are derived fromAeServerApp and both provide the same set of user interface features.CBEServerSampleApp came first and was actually written before there wasan AeServerApp (although the current version derives from AeServerApp).The difference between the two classes is that CBEServerSampleApp alsoderives from AeBEServer, while AeBEServerApp has a AeBEServerApp member(inheritance vs aggregation). Other than that the two classes providethe same set of features:

-   1. Inbound/Outbound message logging—Provides two windows that log    each inbound and outbound message. Makes use of the AeServerApp    logging thread. Logging may be enabled/disabled for either window.-   2. Back-End specific statistics—Gathers and displays statistical    totals such as number of messages sent/received, number of    ACKS/NACKS sent/received, and compressed vs. uncompressed byte    totals.-   3. Application message log view—Provides an additional logging    window that applications should use to log their own errors or trace    statements rather than intermingling them with the system messages    in the system log window.

C. Wizards and Resource Kit of the Intelligent Messaging Network

In a well-known manner, intelligent messaging network can also providetools that work in conjunction with the Microsoft Visual DeveloperStudio framework. These tools assist engineers developing client and BES122 applications, as well as stress test and monitor the health of theintelligent messaging network.

1. Message Builder Wizard

The Intelligent messaging network Message Wizard makes it easy fordevelopers to define their application specific data content of theintelligent messaging network messages. The wizard makes it easier forthe developer to focus on adding business value to their applicationinstead of having to worry about the tedious and error prone task ofwriting the serialization code to transfer message content betweenserver and client. It also automatically generates the code needed toserialize the message content between a client application and a BES 122application.

2. Back End Server App Wizard

The BES 122 App Wizard can make it easy for developers to create BES 122applications. The BES 122 App Wizard generates the Visual Studio C++project and its associated program and header files to create a BES 122executable. BES 122 developers would then need to add program logic tosupport their application protocol.

3. Ping App Wizard

In order to assist engineers developing a BES 122 Ping application, theintelligent Et messaging network Ping App Wizard makes it easy fordevelopers to create a Ping BES 122 executable. The Ping App Wizardgenerates the Visual Studio C++ project and its associated program andheader files to send an application defined “heart beat” message to aBES 122. BES 122 developers may want to use this tool as a way tomonitor the health of their BES 122.

VIII. NT client Simulation Application

In order to assist engineers developing BES 122 s, the intelligentmessaging network can also provide a client simulation application.Developers can use the client simulation application to simulatemultiple clients and to generate BES 122 specific message traffic. Theclient simulation application supports the following major functions:

-   -   Simulate up to 256 clients    -   Support multiple communication networks        -   CDPD        -   Mobitex        -   Dial-Up        -   TCP/IP LAN    -   Configurable simulation attributes        -   Number of messages to send        -   Application defined messages        -   Relative send frequencies for each message type        -   Compression    -   Capture/present performance statistics        -   Total messages sent        -   Average message response time

From the forgoing description it may be appreciated that the presentinvention provides protection against technology obsolescence bysupporting seamless integration of information sources with multiplewireless networks and client devices. As such, the invention provides areliable method of data transfer, while optimizing bandwidth constraintof wireless data services and providing end-to-end security. Thisinvention allows for system growth by incorporating the new devices andwireless network technologies as they become available, without the needto modify client and server applications.

The above-described environment, which has a messaging basearchitecture, serves as the framework for implementation of theinvention. This environment can provide client/server connectivity,which can provide an enabling mechanism for application networkconnection connectivity. The architecture can support messaging.Platform transparency can be provided enabling platform independence ofclient devices 112. Network transparency can be provided by an enablingmechanism for network independence by hiding the underlining networkprotocol. The SDK can provide an easy to use developers tool kit andenvironment for the design development of each aspect of theapplication, the client device 112, and server.

While various exemplary embodiments of the present invention have beendescribed above, it should be understood that they have been presentedby way of example only, and not limitation. Thus, the breadth and scopeof the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

What is claimed is:
 1. A method of accessing a back-end server,comprising: intercepting, via a proxy port, a mobile client web browserrequest from a physical mobile client device; accessing a transportlibrary, independent of a peer wireless protocol, to obtain at least oneof successful transmission information, message segmentationinformation, message retry information, and duplicate messageinformation; re-packaging, with said physical redirector, said mobileclient web browser request; transmitting, via a non-Internet Protocol(IP) protocol, said re-packaged mobile client web browser request to aphysical back-end server; and receiving a response message from saidphysical back-end server.
 2. The method of method of accessing aback-end server according to claim 1, wherein: said mobile client webbrowser request is a Hypertext Transfer Protocol (HTTP) request.
 3. Themethod of method of accessing a back-end server according to claim 1,wherein: said proxy port is an Internet Protocol (IP) proxy port.
 4. Themethod of method of accessing a back-end server according to claim 1,wherein: said non-IP protocol supports at least one of messagesegmentation, message segmentation reassembly, message retries andmessage duplication.
 5. The method of accessing a back-end serveraccording to claim 1, further comprising: accessing, from said physicalmobile client device, said transport library to obtain informationrelated to a wireless protocol supported by said physical mobile clientdevice.
 6. The method of accessing a back-end server according to claim1, wherein: said physical redirector acts as a client side proxy.
 7. Themethod of accessing a back-end server according to claim 1, wherein:said physical redirector provides compression of said mobile client webbrowser request.
 8. The method of accessing a back-end server accordingto claim 1, wherein: said physical redirector provides decompression ofsaid response message to said mobile client web browser request.
 9. Themethod according to claim 1, wherein: said physical redirector unpackssaid response message to said re-packaged mobile client web browserrequest.
 10. A mobile client, comprising: a proxy port to intercept amobile client web browser request from a mobile client device; atransport library, independent of a peer wireless protocol, to obtain atleast one of successful transmission information, message segmentationinformation, message retry information, and duplicate messageinformation; a physical redirector to re-package said mobile client webbrowser request; a transmitter to transmit, via a non-Internet Protocol(IP) protocol, said re-packaged mobile client web browser request to aback-end server; and a receiver to receive a response message from saidphysical back-end server.
 11. The mobile client according to claim 10,wherein: said mobile client web browser request is a Hypertext TransferProtocol (HTTP) request.
 12. The mobile client according to claim 10,wherein: said proxy port is an Internet Protocol (IP) proxy port. 13.The mobile client according to claim 10, wherein: said non-IP protocolsupports at least one of message segmentation, message segmentationreassembly, message retries and message duplication.
 14. The mobileclient according to claim 10, wherein: said transport library,accessible by said mobile client device, provides information related toa wireless protocol supported by said mobile client device.
 15. Themobile client according to claim 10, wherein: said physical redirectoracts as a client side proxy.
 16. The mobile client according to claim10, wherein: said physical redirector provides compression of saidmobile client web browser request.
 17. The mobile client according toclaim 10, wherein: said physical redirector provides decompression ofsaid response message to said mobile client web browser request.
 18. Themobile client according to claim 10, wherein: said redirector unpackssaid response message to said re-packaged mobile client web browserrequest.